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BASH(1)								       BASH(1)

NAME
       bash - GNU Bourne-Again SHell

SYNOPSIS
       bash [options] [command_string |	file]

COPYRIGHT
       Bash is Copyright (C) 1989-2016 by the Free Software Foundation,	Inc.

DESCRIPTION
       Bash  is	 an  sh-compatible  command language interpreter that executes
       commands	read from the standard input or	from a file.  Bash also	incor-
       porates useful features from the	Korn and C shells (ksh and csh).

       Bash  is	 intended  to  be a conformant implementation of the Shell and
       Utilities portion  of  the  IEEE	 POSIX	specification  (IEEE  Standard
       1003.1).	 Bash can be configured	to be POSIX-conformant by default.

OPTIONS
       All of the single-character shell options documented in the description
       of the set builtin command can be used as options  when	the  shell  is
       invoked.	 In addition, bash interprets the following options when it is
       invoked:

       -c	 If the	-c option is present, then commands are	read from  the
		 first non-option argument command_string.  If there are argu-
		 ments	after  the  command_string,  the  first	 argument   is
		 assigned  to  $0  and any remaining arguments are assigned to
		 the positional	parameters.  The assignment  to	 $0  sets  the
		 name  of  the	shell, which is	used in	warning	and error mes-
		 sages.
       -i	 If the	-i option is present, the shell	is interactive.
       -l	 Make bash act as if it	had been invoked as a login shell (see
		 INVOCATION below).
       -r	 If  the  -r  option  is present, the shell becomes restricted
		 (see RESTRICTED SHELL below).
       -s	 If the	-s option is present, or if no arguments remain	 after
		 option	 processing,  then commands are	read from the standard
		 input.	 This option allows the	positional  parameters	to  be
		 set when invoking an interactive shell.
       -D	 A  list of all	double-quoted strings preceded by $ is printed
		 on the	standard output.  These	are the	strings	that are  sub-
		 ject to language translation when the current locale is not C
		 or POSIX.  This implies the -n	option;	no  commands  will  be
		 executed.
       [-+]O [shopt_option]
		 shopt_option  is  one	of  the	 shell options accepted	by the
		 shopt	builtin	 (see  SHELL  BUILTIN  COMMANDS	 below).    If
		 shopt_option is present, -O sets the value of that option; +O
		 unsets	it.  If	shopt_option is	not supplied,  the  names  and
		 values	 of the	shell options accepted by shopt	are printed on
		 the standard output.  If the invocation  option  is  +O,  the
		 output	 is displayed in a format that may be reused as	input.
       --	 A -- signals the end of options and disables  further	option
		 processing.   Any arguments after the -- are treated as file-
		 names and arguments.  An argument of -	is equivalent to --.

       Bash also  interprets  a	 number	 of  multi-character  options.	 These
       options	must  appear  on  the command line before the single-character
       options to be recognized.

       --debugger
	      Arrange for the debugger profile to be executed before the shell
	      starts.	Turns  on extended debugging mode (see the description
	      of the extdebug option to	the shopt builtin below).
       --dump-po-strings
	      Equivalent to -D,	but the	output is in the GNU gettext po	 (por-
	      table object) file format.
       --dump-strings
	      Equivalent to -D.
       --help Display  a  usage	 message  on standard output and exit success-
	      fully.
       --init-file file
       --rcfile	file
	      Execute commands from file instead of the	standard personal ini-
	      tialization  file	 ~/.bashrc  if	the  shell is interactive (see
	      INVOCATION below).

       --login
	      Equivalent to -l.

       --noediting
	      Do not use the GNU readline library to read command  lines  when
	      the shell	is interactive.

       --noprofile
	      Do  not read either the system-wide startup file /etc/profile or
	      any  of  the  personal  initialization  files   ~/.bash_profile,
	      ~/.bash_login,  or  ~/.profile.	By  default,  bash reads these
	      files when it is	invoked	 as  a	login  shell  (see  INVOCATION
	      below).

       --norc Do  not  read  and  execute  the	personal  initialization  file
	      ~/.bashrc	if the shell is	interactive.  This  option  is	on  by
	      default if the shell is invoked as sh.

       --posix
	      Change  the behavior of bash where the default operation differs
	      from the POSIX standard to match the standard (posix mode).  See
	      SEE  ALSO	 below	for a reference	to a document that details how
	      posix mode affects bash's	behavior.

       --restricted
	      The shell	becomes	restricted (see	RESTRICTED SHELL below).

       --verbose
	      Equivalent to -v.

       --version
	      Show version information for this	instance of bash on the	 stan-
	      dard output and exit successfully.

ARGUMENTS
       If arguments remain after option	processing, and	neither	the -c nor the
       -s option has been supplied, the	first argument is assumed  to  be  the
       name  of	 a file	containing shell commands.  If bash is invoked in this
       fashion,	$0 is set to the name of the file, and the positional  parame-
       ters  are set to	the remaining arguments.  Bash reads and executes com-
       mands from this file, then exits.  Bash's exit status is	the exit  sta-
       tus  of	the  last  command executed in the script.  If no commands are
       executed, the exit status is 0.	An attempt is first made to  open  the
       file in the current directory, and, if no file is found,	then the shell
       searches	the directories	in PATH	for the	script.

INVOCATION
       A login shell is	one whose first	character of argument zero is a	-,  or
       one started with	the --login option.

       An  interactive	shell  is  one	started	 without  non-option arguments
       (unless -s is specified)	and without the	-c option whose	standard input
       and error are both connected to terminals (as determined	by isatty(3)),
       or one started with the -i option.  PS1 is set and  $-  includes	 i  if
       bash  is	interactive, allowing a	shell script or	a startup file to test
       this state.

       The following paragraphs	describe how bash executes its startup	files.
       If  any	of  the	files exist but	cannot be read,	bash reports an	error.
       Tildes are expanded in filenames	as described below under Tilde	Expan-
       sion in the EXPANSION section.

       When  bash is invoked as	an interactive login shell, or as a non-inter-
       active shell with the --login option, it	first reads and	executes  com-
       mands  from  the	file /etc/profile, if that file	exists.	 After reading
       that file, it looks for ~/.bash_profile,	~/.bash_login, and ~/.profile,
       in  that	order, and reads and executes commands from the	first one that
       exists and is readable.	The --noprofile	option may be  used  when  the
       shell is	started	to inhibit this	behavior.

       When an interactive login shell exits, or a non-interactive login shell
       executes	the exit builtin command, bash	reads  and  executes  commands
       from the	file ~/.bash_logout, if	it exists.

       When  an	 interactive  shell that is not	a login	shell is started, bash
       reads and executes commands from	~/.bashrc, if that file	exists.	  This
       may  be inhibited by using the --norc option.  The --rcfile file	option
       will force bash to read and  execute  commands  from  file  instead  of
       ~/.bashrc.

       When  bash  is  started	non-interactively,  to run a shell script, for
       example,	it looks for the variable BASH_ENV in the environment, expands
       its  value if it	appears	there, and uses	the expanded value as the name
       of a file to read and execute.  Bash behaves as if the  following  com-
       mand were executed:
	      if [ -n "$BASH_ENV" ]; then . "$BASH_ENV"; fi
       but  the	value of the PATH variable is not used to search for the file-
       name.

       If bash is invoked with the name	sh, it	tries  to  mimic  the  startup
       behavior	 of  historical	 versions  of sh as closely as possible, while
       conforming to the POSIX standard	as well.  When invoked as an  interac-
       tive  login  shell, or a	non-interactive	shell with the --login option,
       it first	attempts to read and execute commands  from  /etc/profile  and
       ~/.profile,  in	that  order.   The  --noprofile	 option	may be used to
       inhibit this behavior.  When invoked as an interactive shell  with  the
       name  sh,  bash	looks for the variable ENV, expands its	value if it is
       defined,	and uses the expanded value as the name	of a file to read  and
       execute.	 Since a shell invoked as sh does not attempt to read and exe-
       cute commands from any other startup files, the --rcfile	option has  no
       effect.	 A  non-interactive  shell  invoked  with the name sh does not
       attempt to read any other startup files.	  When	invoked	 as  sh,  bash
       enters posix mode after the startup files are read.

       When  bash  is  started in posix	mode, as with the --posix command line
       option, it follows the POSIX standard for startup files.	 In this mode,
       interactive  shells  expand  the	ENV variable and commands are read and
       executed	from the file whose name is  the  expanded  value.   No	 other
       startup files are read.

       Bash attempts to	determine when it is being run with its	standard input
       connected to a network connection, as when executed by the remote shell
       daemon,	usually	rshd, or the secure shell daemon sshd.	If bash	deter-
       mines it	is being run in	this fashion, it reads and  executes  commands
       from  ~/.bashrc,	 if  that file exists and is readable.	It will	not do
       this if invoked as sh.  The --norc option may be	used to	 inhibit  this
       behavior,  and the --rcfile option may be used to force another file to
       be read,	but neither rshd nor sshd  generally  invoke  the  shell  with
       those options or	allow them to be specified.

       If the shell is started with the	effective user (group) id not equal to
       the real	user (group) id, and the -p option is not supplied, no startup
       files are read, shell functions are not inherited from the environment,
       the SHELLOPTS, BASHOPTS,	CDPATH,	 and  GLOBIGNORE  variables,  if  they
       appear  in  the	environment, are ignored, and the effective user id is
       set to the real user id.	 If the	-p option is supplied  at  invocation,
       the  startup  behavior  is  the	same, but the effective	user id	is not
       reset.

DEFINITIONS
       The following definitions are used throughout the rest  of  this	 docu-
       ment.
       blank  A	space or tab.
       word   A	 sequence  of  characters  considered  as a single unit	by the
	      shell.  Also known as a token.
       name   A	word consisting	only of	 alphanumeric  characters  and	under-
	      scores,  and beginning with an alphabetic	character or an	under-
	      score.  Also referred to as an identifier.
       metacharacter
	      A	character that,	when unquoted, separates words.	  One  of  the
	      following:
	      |	 & ; ( ) < > space tab newline
       control operator
	      A	token that performs a control function.	 It is one of the fol-
	      lowing symbols:
	      || & && ;	;; ;& ;;& ( ) |	|& <newline>

RESERVED WORDS
       Reserved	words are words	that have a special meaning to the shell.  The
       following words are recognized as reserved when unquoted	and either the
       first word of a simple command (see SHELL GRAMMAR below)	or  the	 third
       word of a case or for command:

       !  case	 coproc	  do  done elif	else esac fi for function if in	select
       then until while	{ } time [[ ]]

SHELL GRAMMAR
   Simple Commands
       A simple	command	is a sequence of optional  variable  assignments  fol-
       lowed  by  blank-separated  words and redirections, and terminated by a
       control operator.  The first word specifies the command to be executed,
       and  is	passed	as  argument  zero.  The remaining words are passed as
       arguments to the	invoked	command.

       The return value	of a simple command is its exit	status,	 or  128+n  if
       the command is terminated by signal n.

   Pipelines
       A  pipeline  is	a sequence of one or more commands separated by	one of
       the control operators | or |&.  The format for a	pipeline is:

	      [time [-p]] [ ! ]	command	[ [|||&] command2 ... ]

       The standard output of command is connected via a pipe to the  standard
       input  of  command2.   This connection is performed before any redirec-
       tions specified by the command (see REDIRECTION below).	If |& is used,
       command's  standard  error, in addition to its standard output, is con-
       nected to command2's standard input through the pipe; it	 is  shorthand
       for  2>&1  |.   This  implicit redirection of the standard error	to the
       standard	output is performed after any redirections  specified  by  the
       command.

       The return status of a pipeline is the exit status of the last command,
       unless the pipefail option is enabled.  If  pipefail  is	 enabled,  the
       pipeline's  return  status is the value of the last (rightmost) command
       to exit with a non-zero status, or zero if all commands	exit  success-
       fully.  If the reserved word !  precedes	a pipeline, the	exit status of
       that pipeline is	the logical negation of	the exit status	 as  described
       above.	The  shell waits for all commands in the pipeline to terminate
       before returning	a value.

       If the time reserved word precedes a pipeline, the elapsed as  well  as
       user  and  system  time consumed	by its execution are reported when the
       pipeline	terminates.  The -p option changes the output format  to  that
       specified  by POSIX.  When the shell is in posix	mode, it does not rec-
       ognize time as a	reserved word if the next token	 begins	 with  a  `-'.
       The  TIMEFORMAT	variable  may be set to	a format string	that specifies
       how the timing information should be displayed; see the description  of
       TIMEFORMAT under	Shell Variables	below.

       When the	shell is in posix mode,	time may be followed by	a newline.  In
       this case, the shell displays the total user and	system	time  consumed
       by  the shell and its children.	The TIMEFORMAT variable	may be used to
       specify the format of the time information.

       Each command in a pipeline is executed as a separate process (i.e.,  in
       a subshell).

   Lists
       A  list	is a sequence of one or	more pipelines separated by one	of the
       operators ;, &, &&, or ||, and optionally terminated by one of ;, &, or
       <newline>.

       Of these	list operators,	&& and || have equal precedence, followed by ;
       and &, which have equal precedence.

       A sequence of one or more newlines may appear in	a list	instead	 of  a
       semicolon to delimit commands.

       If  a  command  is terminated by	the control operator &,	the shell exe-
       cutes the command in the	background in a	subshell.  The shell does  not
       wait  for  the command to finish, and the return	status is 0.  Commands
       separated by a ;	are executed sequentially; the shell  waits  for  each
       command	to terminate in	turn.  The return status is the	exit status of
       the last	command	executed.

       AND and OR lists	are sequences of one or	more  pipelines	 separated  by
       the  &&	and  ||	control	operators, respectively.  AND and OR lists are
       executed	with left associativity.  An AND list has the form

	      command1 && command2

       command2	is executed if,	and only if, command1 returns an  exit	status
       of zero.

       An OR list has the form

	      command1 || command2

       command2	 is  executed  if and only if command1 returns a non-zero exit
       status.	The return status of AND and OR	lists is the  exit  status  of
       the last	command	executed in the	list.

   Compound Commands
       A  compound command is one of the following.  In	most cases a list in a
       command's description may be separated from the rest of the command  by
       one  or	more  newlines,	and may	be followed by a newline in place of a
       semicolon.

       (list) list is executed in a subshell environment (see  COMMAND	EXECU-
	      TION  ENVIRONMENT	below).	 Variable assignments and builtin com-
	      mands that affect	the  shell's  environment  do  not  remain  in
	      effect  after  the  command completes.  The return status	is the
	      exit status of list.

       { list; }
	      list is simply executed in the current shell environment.	  list
	      must  be	terminated with	a newline or semicolon.	 This is known
	      as a group command.  The return status is	 the  exit  status  of
	      list.   Note that	unlike the metacharacters ( and	), { and } are
	      reserved words and must occur where a reserved word is permitted
	      to  be  recognized.   Since they do not cause a word break, they
	      must be separated	from  list  by	whitespace  or	another	 shell
	      metacharacter.

       ((expression))
	      The  expression  is  evaluated  according	to the rules described
	      below under ARITHMETIC EVALUATION.  If the value of the  expres-
	      sion  is	non-zero, the return status is 0; otherwise the	return
	      status is	1.  This is exactly equivalent to let "expression".

       [[ expression ]]
	      Return a status of 0 or 1	depending on  the  evaluation  of  the
	      conditional  expression expression.  Expressions are composed of
	      the primaries described  below  under  CONDITIONAL  EXPRESSIONS.
	      Word  splitting  and pathname expansion are not performed	on the
	      words between the	[[ and	]];  tilde  expansion,	parameter  and
	      variable	expansion, arithmetic expansion, command substitution,
	      process substitution, and	quote removal are  performed.	Condi-
	      tional operators such as -f must be unquoted to be recognized as
	      primaries.

	      When used	with [[, the < and > operators sort  lexicographically
	      using the	current	locale.

	      When  the	 == and	!= operators are used, the string to the right
	      of the operator is considered a pattern and matched according to
	      the rules	described below	under Pattern Matching,	as if the ext-
	      glob shell option	were enabled.  The = operator is equivalent to
	      ==.   If	the  nocasematch shell option is enabled, the match is
	      performed	without	regard to the case of  alphabetic  characters.
	      The  return  value  is  0	if the string matches (==) or does not
	      match (!=) the pattern, and 1 otherwise.	Any part of  the  pat-
	      tern  may	be quoted to force the quoted portion to be matched as
	      a	string.

	      An additional binary operator, =~, is available, with  the  same
	      precedence  as  ==  and  !=.  When it is used, the string	to the
	      right of the operator is considered an extended regular  expres-
	      sion and matched accordingly (as in regex(3)).  The return value
	      is 0 if the string matches the pattern, and 1 otherwise.	If the
	      regular  expression  is syntactically incorrect, the conditional
	      expression's return value	is 2.  If the nocasematch shell	option
	      is enabled, the match is performed without regard	to the case of
	      alphabetic characters.  Any part of the pattern may be quoted to
	      force  the  quoted  portion  to be matched as a string.  Bracket
	      expressions in regular expressions must  be  treated  carefully,
	      since  normal  quoting  characters  lose	their meanings between
	      brackets.	 If the	pattern	is stored in a shell variable, quoting
	      the  variable  expansion forces the entire pattern to be matched
	      as a string.  Substrings matched by parenthesized	subexpressions
	      within  the  regular  expression are saved in the	array variable
	      BASH_REMATCH.  The element of BASH_REMATCH with index 0  is  the
	      portion  of  the	string matching	the entire regular expression.
	      The element of BASH_REMATCH with index n is the portion  of  the
	      string matching the nth parenthesized subexpression.

	      Expressions  may	be  combined  using  the  following operators,
	      listed in	decreasing order of precedence:

	      (	expression )
		     Returns the value of expression.  This  may  be  used  to
		     override the normal precedence of operators.
	      !	expression
		     True if expression	is false.
	      expression1 && expression2
		     True if both expression1 and expression2 are true.
	      expression1 || expression2
		     True if either expression1	or expression2 is true.

	      The && and || operators do not evaluate expression2 if the value
	      of expression1 is	sufficient to determine	the  return  value  of
	      the entire conditional expression.

       for name	[ [ in [ word ... ] ] ;	] do list ; done
	      The list of words	following in is	expanded, generating a list of
	      items.  The variable name	is set to each element of this list in
	      turn,  and  list is executed each	time.  If the in word is omit-
	      ted, the for command executes  list  once	 for  each  positional
	      parameter	that is	set (see PARAMETERS below).  The return	status
	      is the exit status of the	last command that  executes.   If  the
	      expansion	of the items following in results in an	empty list, no
	      commands are executed, and the return status is 0.

       for (( expr1 ; expr2 ; expr3 )) ; do list ; done
	      First, the arithmetic expression expr1 is	evaluated according to
	      the  rules  described  below  under  ARITHMETIC EVALUATION.  The
	      arithmetic expression expr2 is then evaluated  repeatedly	 until
	      it  evaluates  to	zero.  Each time expr2 evaluates to a non-zero
	      value, list is executed and the arithmetic expression  expr3  is
	      evaluated.   If  any  expression is omitted, it behaves as if it
	      evaluates	to 1.  The return value	is the exit status of the last
	      command in list that is executed,	or false if any	of the expres-
	      sions is invalid.

       select name [ in	word ] ; do list ; done
	      The list of words	following in is	expanded, generating a list of
	      items.   The  set	 of  expanded words is printed on the standard
	      error, each preceded by a	number.	 If the	in  word  is  omitted,
	      the  positional  parameters  are printed (see PARAMETERS below).
	      The PS3 prompt is	then displayed and a line read from the	 stan-
	      dard  input.   If	the line consists of a number corresponding to
	      one of the displayed words, then the value of  name  is  set  to
	      that  word.  If the line is empty, the words and prompt are dis-
	      played again.  If	EOF is read, the command completes.  Any other
	      value  read  causes  name	 to  be	set to null.  The line read is
	      saved in the variable REPLY.  The	list is	 executed  after  each
	      selection	until a	break command is executed.  The	exit status of
	      select is	the exit status	of the last command executed in	 list,
	      or zero if no commands were executed.

       case word in [ [(] pattern [ | pattern ]	... ) list ;; ]	... esac
	      A	case command first expands word, and tries to match it against
	      each pattern in turn, using the same matching rules as for path-
	      name  expansion  (see  Pathname  Expansion  below).  The word is
	      expanded using tilde expansion, parameter	 and  variable	expan-
	      sion,  arithmetic	 expansion, command substitution, process sub-
	      stitution	and quote removal.  Each pattern examined is  expanded
	      using  tilde expansion, parameter	and variable expansion,	arith-
	      metic expansion, command substitution, and process substitution.
	      If  the  nocasematch  shell option is enabled, the match is per-
	      formed without regard to	the  case  of  alphabetic  characters.
	      When  a  match is	found, the corresponding list is executed.  If
	      the ;; operator is used, no  subsequent  matches	are  attempted
	      after  the  first	pattern	match.	Using ;& in place of ;;	causes
	      execution	to continue with the list associated with the next set
	      of  patterns.  Using ;;& in place	of ;; causes the shell to test
	      the next pattern list in the statement, if any, and execute  any
	      associated  list on a successful match.  The exit	status is zero
	      if no pattern matches.  Otherwise, it is the exit	status of  the
	      last command executed in list.

       if list;	then list; [ elif list;	then list; ] ... [ else	list; ]	fi
	      The  if  list is executed.  If its exit status is	zero, the then
	      list is executed.	 Otherwise, each  elif	list  is  executed  in
	      turn,  and  if  its  exit	status is zero,	the corresponding then
	      list is executed and the command completes.  Otherwise, the else
	      list  is executed, if present.  The exit status is the exit sta-
	      tus of the last command executed,	or zero	if no condition	tested
	      true.

       while list-1; do	list-2;	done
       until list-1; do	list-2;	done
	      The  while command continuously executes the list	list-2 as long
	      as the last command in the list list-1 returns an	exit status of
	      zero.   The  until  command  is  identical to the	while command,
	      except that the test is negated: list-2 is executed as  long  as
	      the  last	command	in list-1 returns a non-zero exit status.  The
	      exit status of the while and until commands is the  exit	status
	      of the last command executed in list-2, or zero if none was exe-
	      cuted.

   Coprocesses
       A coprocess is a	shell command preceded by the coproc reserved word.  A
       coprocess  is  executed asynchronously in a subshell, as	if the command
       had been	terminated with	the & control operator,	with  a	 two-way  pipe
       established between the executing shell and the coprocess.

       The format for a	coprocess is:

	      coproc [NAME] command [redirections]

       This  creates  a	 coprocess  named  NAME.  If NAME is not supplied, the
       default name is COPROC.	NAME must not be supplied if command is	a sim-
       ple command (see	above);	otherwise, it is interpreted as	the first word
       of the simple command.  When the	coprocess is executed, the shell  cre-
       ates  an	array variable (see Arrays below) named	NAME in	the context of
       the executing shell.  The standard output of command is connected via a
       pipe  to	 a  file  descriptor  in  the  executing  shell, and that file
       descriptor is assigned to NAME[0].  The standard	input  of  command  is
       connected  via  a pipe to a file	descriptor in the executing shell, and
       that file descriptor is assigned	to NAME[1].  This pipe is  established
       before  any  redirections  specified  by	 the  command (see REDIRECTION
       below).	The file descriptors can be utilized  as  arguments  to	 shell
       commands	 and  redirections  using  standard word expansions.  The file
       descriptors are not available in	subshells.   The  process  ID  of  the
       shell spawned to	execute	the coprocess is available as the value	of the
       variable	NAME_PID.  The wait builtin command may	be used	 to  wait  for
       the coprocess to	terminate.

       Since  the  coprocess is	created	as an asynchronous command, the	coproc
       command always returns success.	The return status of  a	 coprocess  is
       the exit	status of command.

   Shell Function Definitions
       A  shell	function is an object that is called like a simple command and
       executes	a compound command with	a new set  of  positional  parameters.
       Shell functions are declared as follows:

       name () compound-command	[redirection]
       function	name [()] compound-command [redirection]
	      This  defines a function named name.  The	reserved word function
	      is optional.  If the function reserved  word  is	supplied,  the
	      parentheses  are optional.  The body of the function is the com-
	      pound command compound-command (see  Compound  Commands  above).
	      That  command is usually a list of commands between { and	}, but
	      may be any command listed	under Compound	Commands  above,  with
	      one  exception:  If  the function	reserved word is used, but the
	      parentheses are not supplied, the	 braces	 are  required.	  com-
	      pound-command is executed	whenever name is specified as the name
	      of a simple command.  When in posix mode,	name may  not  be  the
	      name  of	one  of	 the POSIX special builtins.  Any redirections
	      (see REDIRECTION below) specified	when a function	is defined are
	      performed	 when  the function is executed.  The exit status of a
	      function definition is zero unless a syntax error	 occurs	 or  a
	      readonly	function with the same name already exists.  When exe-
	      cuted, the exit status of	a function is the exit status  of  the
	      last command executed in the body.  (See FUNCTIONS below.)

COMMENTS
       In a non-interactive shell, or an interactive shell in which the	inter-
       active_comments option to the  shopt  builtin  is  enabled  (see	 SHELL
       BUILTIN	COMMANDS  below), a word beginning with	# causes that word and
       all remaining characters	on that	line to	be  ignored.   An  interactive
       shell  without  the  interactive_comments option	enabled	does not allow
       comments.  The interactive_comments option is on	by default in interac-
       tive shells.

QUOTING
       Quoting	is used	to remove the special meaning of certain characters or
       words to	the shell.  Quoting can	be used	to disable  special  treatment
       for special characters, to prevent reserved words from being recognized
       as such,	and to prevent parameter expansion.

       Each of the metacharacters listed above under DEFINITIONS  has  special
       meaning to the shell and	must be	quoted if it is	to represent itself.

       When  the command history expansion facilities are being	used (see HIS-
       TORY EXPANSION below), the history expansion character, usually !, must
       be quoted to prevent history expansion.

       There  are  three  quoting  mechanisms:	the  escape  character,	single
       quotes, and double quotes.

       A non-quoted backslash (\) is the escape	character.  It	preserves  the
       literal value of	the next character that	follows, with the exception of
       <newline>.  If a	\<newline> pair	appears,  and  the  backslash  is  not
       itself  quoted,	the \<newline> is treated as a line continuation (that
       is, it is removed from the input	stream and effectively ignored).

       Enclosing characters in single quotes preserves the  literal  value  of
       each character within the quotes.  A single quote may not occur between
       single quotes, even when	preceded by a backslash.

       Enclosing characters in double quotes preserves the  literal  value  of
       all  characters	within the quotes, with	the exception of $, `, \, and,
       when history expansion is enabled, !.  When the shell is	in posix mode,
       the  !  has  no special meaning within double quotes, even when history
       expansion is enabled.  The characters $	and  `	retain	their  special
       meaning	within double quotes.  The backslash retains its special mean-
       ing only	when followed by one of	the following characters: $, `,	",  \,
       or  <newline>.	A  double  quote may be	quoted within double quotes by
       preceding it with a backslash.  If enabled, history expansion  will  be
       performed  unless  an  !	 appearing in double quotes is escaped using a
       backslash.  The backslash preceding the !  is not removed.

       The special parameters *	and @ have  special  meaning  when  in	double
       quotes (see PARAMETERS below).

       Words of	the form $'string' are treated specially.  The word expands to
       string, with backslash-escaped characters replaced as specified by  the
       ANSI  C	standard.  Backslash escape sequences, if present, are decoded
       as follows:
	      \a     alert (bell)
	      \b     backspace
	      \e
	      \E     an	escape character
	      \f     form feed
	      \n     new line
	      \r     carriage return
	      \t     horizontal	tab
	      \v     vertical tab
	      \\     backslash
	      \'     single quote
	      \"     double quote
	      \?     question mark
	      \nnn   the eight-bit character whose value is  the  octal	 value
		     nnn (one to three digits)
	      \xHH   the  eight-bit  character	whose value is the hexadecimal
		     value HH (one or two hex digits)
	      \uHHHH the Unicode (ISO/IEC 10646) character whose value is  the
		     hexadecimal value HHHH (one to four hex digits)
	      \UHHHHHHHH
		     the  Unicode (ISO/IEC 10646) character whose value	is the
		     hexadecimal value HHHHHHHH	(one to	eight hex digits)
	      \cx    a control-x character

       The expanded result is single-quoted, as	if the	dollar	sign  had  not
       been present.

       A double-quoted string preceded by a dollar sign	($"string") will cause
       the string to be	translated according to	the current  locale.   If  the
       current	locale	is  C  or  POSIX,  the dollar sign is ignored.	If the
       string is translated and	replaced, the replacement is double-quoted.

PARAMETERS
       A parameter is an entity	that stores values.  It	can be a name, a  num-
       ber, or one of the special characters listed below under	Special	Param-
       eters.  A variable is a parameter denoted by a name.  A variable	has  a
       value  and  zero	or more	attributes.  Attributes	are assigned using the
       declare builtin command (see declare below in SHELL BUILTIN  COMMANDS).

       A parameter is set if it	has been assigned a value.  The	null string is
       a valid value.  Once a variable is set, it may be unset only  by	 using
       the unset builtin command (see SHELL BUILTIN COMMANDS below).

       A variable may be assigned to by	a statement of the form

	      name=[value]

       If  value  is not given,	the variable is	assigned the null string.  All
       values undergo tilde expansion, parameter and variable expansion,  com-
       mand  substitution, arithmetic expansion, and quote removal (see	EXPAN-
       SION below).  If	the variable has its integer attribute set, then value
       is evaluated as an arithmetic expression	even if	the $((...)) expansion
       is not used (see	Arithmetic Expansion below).  Word  splitting  is  not
       performed,  with	the exception of "$@" as explained below under Special
       Parameters.  Pathname expansion is not  performed.   Assignment	state-
       ments  may  also	 appear	 as  arguments to the alias, declare, typeset,
       export, readonly, and local builtin  commands  (declaration  commands).
       When in posix mode, these builtins may appear in	a command after	one or
       more instances of the  command  builtin	and  retain  these  assignment
       statement properties.

       In  the context where an	assignment statement is	assigning a value to a
       shell variable or array index, the += operator can be used to append to
       or  add	to  the	variable's previous value.  This includes arguments to
       builtin commands	such as	 declare  that	accept	assignment  statements
       (declaration commands).	When +=	is applied to a	variable for which the
       integer attribute has been set, value is	 evaluated  as	an  arithmetic
       expression  and	added  to  the variable's current value, which is also
       evaluated.  When	+= is applied to  an  array  variable  using  compound
       assignment (see Arrays below), the variable's value is not unset	(as it
       is when using =), and new values	are appended to	the array beginning at
       one  greater  than  the	array's	 maximum index (for indexed arrays) or
       added as	additional key-value pairs  in	an  associative	 array.	  When
       applied	to a string-valued variable, value is expanded and appended to
       the variable's value.

       A variable can be assigned the nameref attribute	using the -n option to
       the  declare or local builtin commands (see the descriptions of declare
       and local below)	to create a nameref, or	a reference to	another	 vari-
       able.   This  allows  variables to be manipulated indirectly.  Whenever
       the nameref variable is referenced, assigned  to,  unset,  or  has  its
       attributes modified (other than using or	changing the nameref attribute
       itself),	the operation is actually performed on the variable  specified
       by  the	nameref	 variable's  value.  A nameref is commonly used	within
       shell functions to refer	to a variable whose name is passed as an argu-
       ment  to	the function.  For instance, if	a variable name	is passed to a
       shell function as its first argument, running
	      declare -n ref=$1
       inside the function creates a nameref variable ref whose	value  is  the
       variable	name passed as the first argument.  References and assignments
       to ref, and changes to  its  attributes,	 are  treated  as  references,
       assignments, and	attribute modifications	to the variable	whose name was
       passed as $1.  If the control variable in a for loop  has  the  nameref
       attribute,  the	list  of words can be a	list of	shell variables, and a
       name reference will be established for each word	in the list, in	 turn,
       when the	loop is	executed.  Array variables cannot be given the nameref
       attribute.  However, nameref variables can  reference  array  variables
       and  subscripted	 array	variables.  Namerefs can be unset using	the -n
       option to the unset builtin.  Otherwise,	if unset is executed with  the
       name  of	 a nameref variable as an argument, the	variable referenced by
       the nameref variable will be unset.

   Positional Parameters
       A positional parameter is a parameter denoted by	one  or	 more  digits,
       other than the single digit 0.  Positional parameters are assigned from
       the shell's arguments when it is	invoked, and may be  reassigned	 using
       the  set	builtin	command.  Positional parameters	may not	be assigned to
       with assignment statements.  The	positional parameters are  temporarily
       replaced	when a shell function is executed (see FUNCTIONS below).

       When  a	positional parameter consisting	of more	than a single digit is
       expanded, it must be enclosed in	braces (see EXPANSION below).

   Special Parameters
       The shell treats	several	parameters specially.	These  parameters  may
       only be referenced; assignment to them is not allowed.
       *      Expands  to  the positional parameters, starting from one.  When
	      the expansion is	not  within  double  quotes,  each  positional
	      parameter	 expands  to a separate	word.  In contexts where it is
	      performed, those words are subject to further word splitting and
	      pathname	expansion.   When  the	expansion occurs within	double
	      quotes, it expands to a single  word  with  the  value  of  each
	      parameter	 separated  by	the first character of the IFS special
	      variable.	 That is, "$*" is equivalent to	"$1c$2c...",  where  c
	      is the first character of	the value of the IFS variable.	If IFS
	      is unset,	the parameters are separated by	 spaces.   If  IFS  is
	      null,  the parameters are	joined without intervening separators.
       @      Expands to the positional	parameters, starting from  one.	  When
	      the  expansion  occurs  within  double  quotes,  each  parameter
	      expands to a separate word.  That	is, "$@" is equivalent to "$1"
	      "$2"  ...	  If the double-quoted expansion occurs	within a word,
	      the expansion of the first parameter is joined with  the	begin-
	      ning  part  of  the original word, and the expansion of the last
	      parameter	is joined with the last	part  of  the  original	 word.
	      When  there  are no positional parameters, "$@" and $@ expand to
	      nothing (i.e., they are removed).
       #      Expands to the number of positional parameters in	decimal.
       ?      Expands to the exit status of the	most recently  executed	 fore-
	      ground pipeline.
       -      Expands  to  the	current	option flags as	specified upon invoca-
	      tion, by the set builtin command,	or  those  set	by  the	 shell
	      itself (such as the -i option).
       $      Expands  to  the	process	ID of the shell.  In a () subshell, it
	      expands to the process ID	of the current	shell,	not  the  sub-
	      shell.
       !      Expands  to  the process ID of the job most recently placed into
	      the background, whether executed as an asynchronous  command  or
	      using the	bg builtin (see	JOB CONTROL below).
       0      Expands  to  the name of the shell or shell script.  This	is set
	      at shell initialization.	If bash	is invoked with	a file of com-
	      mands,  $0  is set to the	name of	that file.  If bash is started
	      with the -c option, then $0 is set to the	first  argument	 after
	      the  string to be	executed, if one is present.  Otherwise, it is
	      set to the filename used to invoke bash, as  given  by  argument
	      zero.
       _      At  shell	 startup,  set to the absolute pathname	used to	invoke
	      the shell	or shell script	being executed as passed in the	 envi-
	      ronment  or  argument  list.   Subsequently, expands to the last
	      argument to the previous command,	after expansion.  Also set  to
	      the  full	 pathname  used	 to  invoke  each command executed and
	      placed in	the environment	exported to that command.  When	check-
	      ing  mail,  this	parameter holds	the name of the	mail file cur-
	      rently being checked.

   Shell Variables
       The following variables are set by the shell:

       BASH   Expands to the full filename used	to  invoke  this  instance  of
	      bash.
       BASHOPTS
	      A	 colon-separated  list of enabled shell	options.  Each word in
	      the list is a valid argument for the  -s	option	to  the	 shopt
	      builtin command (see SHELL BUILTIN COMMANDS below).  The options
	      appearing	in BASHOPTS are	those reported as  on  by  shopt.   If
	      this  variable  is  in the environment when bash starts up, each
	      shell option in the list will  be	 enabled  before  reading  any
	      startup files.  This variable is read-only.
       BASHPID
	      Expands  to  the	process	 ID of the current bash	process.  This
	      differs from $$ under certain circumstances, such	 as  subshells
	      that do not require bash to be re-initialized.
       BASH_ALIASES
	      An  associative  array  variable whose members correspond	to the
	      internal list of aliases as maintained  by  the  alias  builtin.
	      Elements	added to this array appear in the alias	list; however,
	      unsetting	array elements currently does not cause	aliases	to  be
	      removed from the alias list.  If BASH_ALIASES is unset, it loses
	      its special properties, even if it is subsequently reset.
       BASH_ARGC
	      An array variable	whose values are the number of	parameters  in
	      each frame of the	current	bash execution call stack.  The	number
	      of parameters to	the  current  subroutine  (shell  function  or
	      script  executed	with  .	or source) is at the top of the	stack.
	      When a subroutine	is executed, the number	of  parameters	passed
	      is pushed	onto BASH_ARGC.	 The shell sets	BASH_ARGC only when in
	      extended debugging mode (see the	description  of	 the  extdebug
	      option to	the shopt builtin below)
       BASH_ARGV
	      An  array	 variable containing all of the	parameters in the cur-
	      rent bash	execution call stack.  The final parameter of the last
	      subroutine  call is at the top of	the stack; the first parameter
	      of the initial call is at	the bottom.  When a subroutine is exe-
	      cuted,  the  parameters supplied are pushed onto BASH_ARGV.  The
	      shell sets BASH_ARGV only	when in	extended debugging  mode  (see
	      the  description	of  the	 extdebug  option to the shopt builtin
	      below)
       BASH_CMDS
	      An associative array variable whose members  correspond  to  the
	      internal	hash  table  of	 commands  as  maintained  by the hash
	      builtin.	Elements added to this array appear in the hash	table;
	      however,	unsetting array	elements currently does	not cause com-
	      mand names to be removed from the	hash table.  If	 BASH_CMDS  is
	      unset,  it  loses	 its  special properties, even if it is	subse-
	      quently reset.
       BASH_COMMAND
	      The command currently being executed or about  to	 be  executed,
	      unless the shell is executing a command as the result of a trap,
	      in which case it is the command executing	at  the	 time  of  the
	      trap.
       BASH_EXECUTION_STRING
	      The command argument to the -c invocation	option.
       BASH_LINENO
	      An  array	 variable whose	members	are the	line numbers in	source
	      files where each corresponding member of FUNCNAME	 was  invoked.
	      ${BASH_LINENO[$i]}  is  the  line	 number	 in  the  source  file
	      (${BASH_SOURCE[$i+1]})  where  ${FUNCNAME[$i]}  was  called  (or
	      ${BASH_LINENO[$i-1]}  if	referenced  within another shell func-
	      tion).  Use LINENO to obtain the current line number.
       BASH_LOADABLES_PATH
	      A	colon-separated	list of	directories in which the  shell	 looks
	      for  dynamically	loadable builtins specified by the enable com-
	      mand.
       BASH_REMATCH
	      An array variable	whose members are assigned by  the  =~	binary
	      operator	to the [[ conditional command.	The element with index
	      0	is the portion of  the	string	matching  the  entire  regular
	      expression.   The	 element  with	index  n is the	portion	of the
	      string matching the nth parenthesized subexpression.  This vari-
	      able is read-only.
       BASH_SOURCE
	      An  array	 variable whose	members	are the	source filenames where
	      the corresponding	shell function names  in  the  FUNCNAME	 array
	      variable	are  defined.	The  shell function ${FUNCNAME[$i]} is
	      defined  in  the	file  ${BASH_SOURCE[$i]}   and	 called	  from
	      ${BASH_SOURCE[$i+1]}.
       BASH_SUBSHELL
	      Incremented  by one within each subshell or subshell environment
	      when the shell begins executing in that environment.   The  ini-
	      tial value is 0.
       BASH_VERSINFO
	      A	readonly array variable	whose members hold version information
	      for this instance	of bash.  The values  assigned	to  the	 array
	      members are as follows:
	      BASH_VERSINFO[0]	      The  major version number	(the release).
	      BASH_VERSINFO[1]	      The minor	version	number (the  version).
	      BASH_VERSINFO[2]	      The patch	level.
	      BASH_VERSINFO[3]	      The build	version.
	      BASH_VERSINFO[4]	      The release status (e.g.,	beta1).
	      BASH_VERSINFO[5]	      The value	of MACHTYPE.
       BASH_VERSION
	      Expands  to  a string describing the version of this instance of
	      bash.
       COMP_CWORD
	      An index into ${COMP_WORDS} of the word containing  the  current
	      cursor position.	This variable is available only	in shell func-
	      tions invoked by the  programmable  completion  facilities  (see
	      Programmable Completion below).
       COMP_KEY
	      The key (or final	key of a key sequence) used to invoke the cur-
	      rent completion function.
       COMP_LINE
	      The current command line.	 This variable is  available  only  in
	      shell  functions	and  external  commands	 invoked  by  the pro-
	      grammable	completion  facilities	(see  Programmable  Completion
	      below).
       COMP_POINT
	      The  index of the	current	cursor position	relative to the	begin-
	      ning of the current command.  If the current cursor position  is
	      at the end of the	current	command, the value of this variable is
	      equal to ${#COMP_LINE}.  This  variable  is  available  only  in
	      shell  functions	and  external  commands	 invoked  by  the pro-
	      grammable	completion  facilities	(see  Programmable  Completion
	      below).
       COMP_TYPE
	      Set  to an integer value corresponding to	the type of completion
	      attempted	that caused a completion function to be	 called:  TAB,
	      for  normal completion, ?, for listing completions after succes-
	      sive tabs, !, for	listing	alternatives on	partial	 word  comple-
	      tion,  @,	 to list completions if	the word is not	unmodified, or
	      %, for menu completion.  This  variable  is  available  only  in
	      shell  functions	and  external  commands	 invoked  by  the pro-
	      grammable	completion  facilities	(see  Programmable  Completion
	      below).
       COMP_WORDBREAKS
	      The  set	of characters that the readline	library	treats as word
	      separators when performing word completion.  If  COMP_WORDBREAKS
	      is  unset, it loses its special properties, even if it is	subse-
	      quently reset.
       COMP_WORDS
	      An array variable	(see Arrays below) consisting of the  individ-
	      ual  words  in the current command line.	The line is split into
	      words as readline	 would	split  it,  using  COMP_WORDBREAKS  as
	      described	above.	This variable is available only	in shell func-
	      tions invoked by the  programmable  completion  facilities  (see
	      Programmable Completion below).
       COPROC An  array	 variable  (see	Arrays below) created to hold the file
	      descriptors for output from and input to	an  unnamed  coprocess
	      (see Coprocesses above).
       DIRSTACK
	      An array variable	(see Arrays below) containing the current con-
	      tents of the directory stack.  Directories appear	in  the	 stack
	      in  the order they are displayed by the dirs builtin.  Assigning
	      to members of this array variable	may be used to modify directo-
	      ries  already in the stack, but the pushd	and popd builtins must
	      be used to add and remove	directories.  Assignment to this vari-
	      able  will  not  change  the  current directory.	If DIRSTACK is
	      unset, it	loses its special properties, even  if	it  is	subse-
	      quently reset.
       EUID   Expands  to  the effective user ID of the	current	user, initial-
	      ized at shell startup.  This variable is readonly.
       FUNCNAME
	      An array variable	containing the names of	 all  shell  functions
	      currently	in the execution call stack.  The element with index 0
	      is the name of any currently-executing shell function.  The bot-
	      tom-most	element	 (the  one  with the highest index) is "main".
	      This variable exists only	when a shell  function	is  executing.
	      Assignments  to  FUNCNAME	have no	effect.	 If FUNCNAME is	unset,
	      it loses its special properties,	even  if  it  is  subsequently
	      reset.

	      This  variable  can  be  used  with BASH_LINENO and BASH_SOURCE.
	      Each  element  of	 FUNCNAME  has	 corresponding	 elements   in
	      BASH_LINENO  and	BASH_SOURCE  to	 describe the call stack.  For
	      instance,	  ${FUNCNAME[$i]}   was	  called   from	   the	  file
	      ${BASH_SOURCE[$i+1]}  at	line  number  ${BASH_LINENO[$i]}.  The
	      caller builtin displays the current call stack using this	infor-
	      mation.
       GROUPS An  array	 variable  containing  the list	of groups of which the
	      current user is a	member.	 Assignments to	GROUPS have no effect.
	      If  GROUPS is unset, it loses its	special	properties, even if it
	      is subsequently reset.
       HISTCMD
	      The history number, or index in the history list,	of the current
	      command.	 If HISTCMD is unset, it loses its special properties,
	      even if it is subsequently reset.
       HOSTNAME
	      Automatically set	to the name of the current host.
       HOSTTYPE
	      Automatically set	to a string that uniquely describes  the  type
	      of  machine  on which bash is executing.	The default is system-
	      dependent.
       LINENO Each time	this parameter is referenced, the shell	substitutes  a
	      decimal  number  representing the	current	sequential line	number
	      (starting	with 1)	within a script	or function.  When  not	 in  a
	      script  or  function, the	value substituted is not guaranteed to
	      be meaningful.  If LINENO	is unset, it loses its special proper-
	      ties, even if it is subsequently reset.
       MACHTYPE
	      Automatically  set  to  a	string that fully describes the	system
	      type on which bash is executing, in the  standard	 GNU  cpu-com-
	      pany-system format.  The default is system-dependent.
       MAPFILE
	      An  array	 variable  (see	Arrays below) created to hold the text
	      read by the mapfile builtin when no variable name	is supplied.
       OLDPWD The previous working directory as	set by the cd command.
       OPTARG The value	of the last option argument processed by  the  getopts
	      builtin command (see SHELL BUILTIN COMMANDS below).
       OPTIND The  index  of  the next argument	to be processed	by the getopts
	      builtin command (see SHELL BUILTIN COMMANDS below).
       OSTYPE Automatically set	to a string that describes the operating  sys-
	      tem  on  which  bash is executing.  The default is system-depen-
	      dent.
       PIPESTATUS
	      An array variable	(see Arrays below) containing a	list  of  exit
	      status  values  from the processes in the	most-recently-executed
	      foreground pipeline (which may contain only a single command).
       PPID   The process ID of	the shell's parent.  This  variable  is	 read-
	      only.
       PWD    The current working directory as set by the cd command.
       RANDOM Each time	this parameter is referenced, a	random integer between
	      0	and 32767 is generated.	 The sequence of random	numbers	may be
	      initialized by assigning a value to RANDOM.  If RANDOM is	unset,
	      it loses its special properties,	even  if  it  is  subsequently
	      reset.
       READLINE_LINE
	      The contents of the readline line	buffer,	for use	with "bind -x"
	      (see SHELL BUILTIN COMMANDS below).
       READLINE_POINT
	      The position of the insertion point in the readline line buffer,
	      for use with "bind -x" (see SHELL	BUILTIN	COMMANDS below).
       REPLY  Set  to  the line	of input read by the read builtin command when
	      no arguments are supplied.
       SECONDS
	      Each time	this parameter is referenced, the  number  of  seconds
	      since  shell  invocation is returned.  If	a value	is assigned to
	      SECONDS, the value returned upon subsequent  references  is  the
	      number  of seconds since the assignment plus the value assigned.
	      If SECONDS is unset, it loses its	special	properties, even if it
	      is subsequently reset.
       SHELLOPTS
	      A	 colon-separated  list of enabled shell	options.  Each word in
	      the list is a valid argument  for	 the  -o  option  to  the  set
	      builtin command (see SHELL BUILTIN COMMANDS below).  The options
	      appearing	in SHELLOPTS are those reported	as on by set  -o.   If
	      this  variable  is  in the environment when bash starts up, each
	      shell option in the list will  be	 enabled  before  reading  any
	      startup files.  This variable is read-only.
       SHLVL  Incremented by one each time an instance of bash is started.
       UID    Expands to the user ID of	the current user, initialized at shell
	      startup.	This variable is readonly.

       The following variables are used	by the shell.	In  some  cases,  bash
       assigns a default value to a variable; these cases are noted below.

       BASH_COMPAT
	      The  value  is used to set the shell's compatibility level.  See
	      the description of the shopt builtin below under	SHELL  BUILTIN
	      COMMANDS	for  a description of the various compatibility	levels
	      and their	effects.  The value may	be  a  decimal	number	(e.g.,
	      4.2)  or an integer (e.g., 42) corresponding to the desired com-
	      patibility level.	 If BASH_COMPAT	is unset or set	to  the	 empty
	      string,  the  compatibility  level is set	to the default for the
	      current version.	If BASH_COMPAT is set to a value that  is  not
	      one of the valid compatibility levels, the shell prints an error
	      message and sets the compatibility level to the default for  the
	      current  version.	  The valid compatibility levels correspond to
	      the  compatibility  options  accepted  by	 the   shopt   builtin
	      described	below (for example, compat42 means that	4.2 and	42 are
	      valid values).  The current version is also a valid value.
       BASH_ENV
	      If this parameter	is set when bash is executing a	shell  script,
	      its  value  is  interpreted as a filename	containing commands to
	      initialize the shell, as in ~/.bashrc.  The value	of BASH_ENV is
	      subjected	 to  parameter	expansion,  command  substitution, and
	      arithmetic expansion before being	 interpreted  as  a  filename.
	      PATH is not used to search for the resultant filename.
       BASH_XTRACEFD
	      If  set  to an integer corresponding to a	valid file descriptor,
	      bash will	write the  trace  output  generated  when  set	-x  is
	      enabled  to that file descriptor.	 The file descriptor is	closed
	      when BASH_XTRACEFD is unset or assigned a	new value.   Unsetting
	      BASH_XTRACEFD  or	assigning it the empty string causes the trace
	      output to	be sent	to the	standard  error.   Note	 that  setting
	      BASH_XTRACEFD to 2 (the standard error file descriptor) and then
	      unsetting	it will	result in the standard error being closed.
       CDPATH The search path for the cd command.  This	is  a  colon-separated
	      list  of	directories  in	 which the shell looks for destination
	      directories specified by the cd  command.	  A  sample  value  is
	      ".:~:/usr".
       CHILD_MAX
	      Set  the	number	of exited child	status values for the shell to
	      remember.	 Bash will not allow this value	to be decreased	 below
	      a	 POSIX-mandated	 minimum,  and	there is a maximum value (cur-
	      rently 8192) that	this may not exceed.   The  minimum  value  is
	      system-dependent.
       COLUMNS
	      Used  by	the  select compound command to	determine the terminal
	      width when printing selection lists.  Automatically set  if  the
	      checkwinsize  option  is enabled or in an	interactive shell upon
	      receipt of a SIGWINCH.
       COMPREPLY
	      An array variable	from which bash	reads the possible completions
	      generated	 by  a shell function invoked by the programmable com-
	      pletion facility	(see  Programmable  Completion	below).	  Each
	      array element contains one possible completion.
       EMACS  If  bash	finds  this variable in	the environment	when the shell
	      starts with value	"t", it	assumes	that the shell is  running  in
	      an Emacs shell buffer and	disables line editing.
       ENV    Similar  to  BASH_ENV;  used  when the shell is invoked in POSIX
	      mode.
       EXECIGNORE
	      A	colon-separated	list of	shell patterns (see Pattern  Matching)
	      defining	the  list of filenames to be ignored by	command	search
	      using PATH.  Files whose full pathnames match one	of these  pat-
	      terns  are  not  considered executable files for the purposes of
	      completion and command execution via PATH	lookup.	 This does not
	      affect the behavior of the [, test, and [[ commands.  Full path-
	      names in the command hash	table are not subject  to  EXECIGNORE.
	      Use  this	 variable to ignore shared library files that have the
	      executable bit set, but are not executable files.	  The  pattern
	      matching honors the setting of the extglob shell option.
       FCEDIT The default editor for the fc builtin command.
       FIGNORE
	      A	 colon-separated  list	of  suffixes to	ignore when performing
	      filename completion (see READLINE	below).	 A filename whose suf-
	      fix  matches  one	of the entries in FIGNORE is excluded from the
	      list of matched filenames.  A sample value is ".o:~".
       FUNCNEST
	      If set to	a numeric value	greater	 than  0,  defines  a  maximum
	      function	nesting	 level.	 Function invocations that exceed this
	      nesting level will cause the current command to abort.
       GLOBIGNORE
	      A	colon-separated	list of	patterns defining the set of filenames
	      to be ignored by pathname	expansion.  If a filename matched by a
	      pathname expansion pattern also matches one of the  patterns  in
	      GLOBIGNORE, it is	removed	from the list of matches.
       HISTCONTROL
	      A	 colon-separated  list	of values controlling how commands are
	      saved on the history list.   If  the  list  of  values  includes
	      ignorespace,  lines  which  begin	with a space character are not
	      saved in the history list.  A value of ignoredups	 causes	 lines
	      matching the previous history entry to not be saved.  A value of
	      ignoreboth is shorthand for ignorespace and ignoredups.  A value
	      of erasedups causes all previous lines matching the current line
	      to be removed from the history list before that line  is	saved.
	      Any  value  not in the above list	is ignored.  If	HISTCONTROL is
	      unset, or	does not include a valid value,	all lines read by  the
	      shell parser are saved on	the history list, subject to the value
	      of HISTIGNORE.  The second and subsequent	lines of a  multi-line
	      compound	command	 are  not tested, and are added	to the history
	      regardless of the	value of HISTCONTROL.
       HISTFILE
	      The name of the file in which command history is saved (see HIS-
	      TORY  below).   The default value	is ~/.bash_history.  If	unset,
	      the command history is not saved when a shell exits.
       HISTFILESIZE
	      The maximum number of lines contained in the history file.  When
	      this  variable  is  assigned  a value, the history file is trun-
	      cated, if	necessary, to contain no  more	than  that  number  of
	      lines  by	removing the oldest entries.  The history file is also
	      truncated	to this	size after writing it when a shell exits.   If
	      the  value  is  0,  the  history file is truncated to zero size.
	      Non-numeric values and numeric values  less  than	 zero  inhibit
	      truncation.   The	 shell	sets the default value to the value of
	      HISTSIZE after reading any startup files.
       HISTIGNORE
	      A	colon-separated	list of	patterns used to decide	which  command
	      lines  should  be	 saved	on  the	history	list.  Each pattern is
	      anchored at the beginning	of the line and	must  match  the  com-
	      plete  line  (no	implicit  `*'  is  appended).  Each pattern is
	      tested against the line after the	checks specified  by  HISTCON-
	      TROL  are	 applied.   In	addition  to  the normal shell pattern
	      matching characters, `&' matches the previous history line.  `&'
	      may  be  escaped	using  a  backslash;  the backslash is removed
	      before attempting	a match.  The second and subsequent lines of a
	      multi-line compound command are not tested, and are added	to the
	      history regardless of the	 value	of  HISTIGNORE.	  The  pattern
	      matching honors the setting of the extglob shell option.
       HISTSIZE
	      The  number  of commands to remember in the command history (see
	      HISTORY below).  If the value is 0, commands are	not  saved  in
	      the history list.	 Numeric values	less than zero result in every
	      command being saved on the history list  (there  is  no  limit).
	      The  shell  sets	the  default  value  to	 500 after reading any
	      startup files.
       HISTTIMEFORMAT
	      If this variable is set and not null, its	value  is  used	 as  a
	      format string for	strftime(3) to print the time stamp associated
	      with each	history	entry displayed	by the	history	 builtin.   If
	      this  variable  is  set,	time stamps are	written	to the history
	      file so they may be preserved across shell sessions.  This  uses
	      the  history  comment  character	to distinguish timestamps from
	      other history lines.
       HOME   The home directory of the	current	user; the default argument for
	      the cd builtin command.  The value of this variable is also used
	      when performing tilde expansion.
       HOSTFILE
	      Contains the name	of a file in the  same	format	as  /etc/hosts
	      that should be read when the shell needs to complete a hostname.
	      The list of possible hostname completions	may be	changed	 while
	      the  shell  is  running;	the  next  time	hostname completion is
	      attempted	after the value	is changed, bash adds the contents  of
	      the  new file to the existing list.  If HOSTFILE is set, but has
	      no value,	or does	not name a readable  file,  bash  attempts  to
	      read  /etc/hosts to obtain the list of possible hostname comple-
	      tions.  When HOSTFILE is unset, the hostname list	is cleared.
       IFS    The Internal Field Separator that	is  used  for  word  splitting
	      after  expansion	and  to	 split	lines into words with the read
	      builtin  command.	  The  default	value  is  ``<space><tab><new-
	      line>''.
       IGNOREEOF
	      Controls the action of an	interactive shell on receipt of	an EOF
	      character	as the sole input.  If set, the	value is the number of
	      consecutive  EOF	characters  which  must	 be typed as the first
	      characters on an input line before bash exits.  If the  variable
	      exists  but  does	not have a numeric value, or has no value, the
	      default value is 10.  If it does not exist,  EOF	signifies  the
	      end of input to the shell.
       INPUTRC
	      The  filename  for  the  readline	 startup  file,	overriding the
	      default of ~/.inputrc (see READLINE below).
       LANG   Used to determine	the  locale  category  for  any	 category  not
	      specifically selected with a variable starting with LC_.
       LC_ALL This  variable  overrides	 the  value  of	LANG and any other LC_
	      variable specifying a locale category.
       LC_COLLATE
	      This variable determines the collation order used	 when  sorting
	      the  results  of pathname	expansion, and determines the behavior
	      of  range	 expressions,  equivalence  classes,   and   collating
	      sequences	within pathname	expansion and pattern matching.
       LC_CTYPE
	      This  variable  determines  the interpretation of	characters and
	      the behavior of character	classes	within pathname	expansion  and
	      pattern matching.
       LC_MESSAGES
	      This  variable  determines  the locale used to translate double-
	      quoted strings preceded by a $.
       LC_NUMERIC
	      This variable determines the locale  category  used  for	number
	      formatting.
       LC_TIME
	      This  variable  determines the locale category used for data and
	      time formatting.
       LINES  Used by the select compound  command  to	determine  the	column
	      length  for  printing selection lists.  Automatically set	if the
	      checkwinsize option is enabled or	in an interactive  shell  upon
	      receipt of a SIGWINCH.
       MAIL   If  this	parameter  is  set to a	file or	directory name and the
	      MAILPATH variable	is not set,  bash  informs  the	 user  of  the
	      arrival  of  mail	in the specified file or Maildir-format	direc-
	      tory.
       MAILCHECK
	      Specifies	how often (in seconds)	bash  checks  for  mail.   The
	      default  is  60 seconds.	When it	is time	to check for mail, the
	      shell does so before displaying the  primary  prompt.   If  this
	      variable	is  unset,  or	set  to	 a  value that is not a	number
	      greater than or equal to zero, the shell disables	mail checking.
       MAILPATH
	      A	colon-separated	list of	filenames to be	checked	for mail.  The
	      message to be printed when mail arrives in a particular file may
	      be  specified by separating the filename from the	message	with a
	      `?'.  When used in the text of the message, $_  expands  to  the
	      name of the current mailfile.  Example:
	      MAILPATH='/var/mail/bfox?"You  have  mail":~/shell-mail?"$_  has
	      mail!"'
	      Bash can be configured to	supply a default value for this	 vari-
	      able  (there  is	no  value by default), but the location	of the
	      user  mail  files	 that  it  uses	 is  system  dependent	(e.g.,
	      /var/mail/$USER).
       OPTERR If set to	the value 1, bash displays error messages generated by
	      the getopts builtin command (see SHELL BUILTIN COMMANDS  below).
	      OPTERR  is  initialized to 1 each	time the shell is invoked or a
	      shell script is executed.
       PATH   The search path for commands.  It	is a colon-separated  list  of
	      directories  in  which the shell looks for commands (see COMMAND
	      EXECUTION	below).	 A zero-length (null) directory	 name  in  the
	      value of PATH indicates the current directory.  A	null directory
	      name may appear as two adjacent colons,  or  as  an  initial  or
	      trailing	colon.	 The  default path is system-dependent,	and is
	      set by the administrator who installs bash.  A common value is
	      ``/usr/local/bin:/usr/local/sbin:/usr/bin:/usr/sbin:/bin:/sbin''.
       POSIXLY_CORRECT
	      If this variable is in the environment  when  bash  starts,  the
	      shell  enters posix mode before reading the startup files, as if
	      the --posix invocation option had	been supplied.	If it  is  set
	      while  the  shell	is running, bash enables posix mode, as	if the
	      command set -o posix had been executed.
       PROMPT_COMMAND
	      If set, the value	is executed as a command prior to issuing each
	      primary prompt.
       PROMPT_DIRTRIM
	      If  set  to a number greater than	zero, the value	is used	as the
	      number of	trailing directory components to retain	when expanding
	      the  \w  and  \W	prompt	string	escapes	(see PROMPTING below).
	      Characters removed are replaced with an ellipsis.
       PS0    The value	of this	parameter is expanded  (see  PROMPTING	below)
	      and  displayed by	interactive shells after reading a command and
	      before the command is executed.
       PS1    The value	of this	parameter is expanded  (see  PROMPTING	below)
	      and  used	 as  the  primary prompt string.  The default value is
	      ``\u@\h\$	''.
       PS2    The value	of this	parameter is expanded as with PS1 and used  as
	      the secondary prompt string.  The	default	is ``> ''.
       PS3    The value	of this	parameter is used as the prompt	for the	select
	      command (see SHELL GRAMMAR above).
       PS4    The value	of this	parameter is expanded  as  with	 PS1  and  the
	      value  is	 printed  before  each command bash displays during an
	      execution	trace.	The first character of PS4 is replicated  mul-
	      tiple  times, as necessary, to indicate multiple levels of indi-
	      rection.	The default is ``+ ''.
       SHELL  The full pathname	to the shell is	kept in	this environment vari-
	      able.   If  it is	not set	when the shell starts, bash assigns to
	      it the full pathname of the current user's login shell.
       TIMEFORMAT
	      The value	of this	parameter is used as a format string  specify-
	      ing  how	the timing information for pipelines prefixed with the
	      time reserved word should	be displayed.  The % character	intro-
	      duces  an	 escape	 sequence  that	is expanded to a time value or
	      other information.  The escape sequences and their meanings  are
	      as follows; the braces denote optional portions.
	      %%	A literal %.
	      %[p][l]R	The elapsed time in seconds.
	      %[p][l]U	The number of CPU seconds spent	in user	mode.
	      %[p][l]S	The number of CPU seconds spent	in system mode.
	      %P	The CPU	percentage, computed as	(%U + %S) / %R.

	      The  optional  p is a digit specifying the precision, the	number
	      of fractional digits after a decimal point.  A value of 0	causes
	      no decimal point or fraction to be output.  At most three	places
	      after the	decimal	point may be specified;	values	of  p  greater
	      than  3 are changed to 3.	 If p is not specified,	the value 3 is
	      used.

	      The optional l specifies a longer	format,	including minutes,  of
	      the  form	 MMmSS.FFs.   The value	of p determines	whether	or not
	      the fraction is included.

	      If this variable is not set, bash	acts as	if it  had  the	 value
	      $'\nreal\t%3lR\nuser\t%3lU\nsys\t%3lS'.	If  the	value is null,
	      no timing	information is displayed.  A trailing newline is added
	      when the format string is	displayed.
       TMOUT  If  set  to  a  value greater than zero, TMOUT is	treated	as the
	      default timeout for the read builtin.  The select	command	termi-
	      nates if input does not arrive after TMOUT seconds when input is
	      coming from a terminal.  In an interactive shell,	the  value  is
	      interpreted as the number	of seconds to wait for a line of input
	      after issuing the	primary	prompt.	 Bash terminates after waiting
	      for  that	number of seconds if a complete	line of	input does not
	      arrive.
       TMPDIR If set, bash uses	its value as the name of a directory in	 which
	      bash creates temporary files for the shell's use.
       auto_resume
	      This variable controls how the shell interacts with the user and
	      job control.  If this variable is	set, single word  simple  com-
	      mands without redirections are treated as	candidates for resump-
	      tion of an existing stopped job.	There is no ambiguity allowed;
	      if  there	 is more than one job beginning	with the string	typed,
	      the job most recently accessed  is  selected.   The  name	 of  a
	      stopped  job, in this context, is	the command line used to start
	      it.  If set to the value exact, the string supplied  must	 match
	      the  name	 of  a	stopped	 job exactly; if set to	substring, the
	      string supplied needs to match a substring  of  the  name	 of  a
	      stopped  job.  The substring value provides functionality	analo-
	      gous to the %?  job identifier (see JOB CONTROL below).  If  set
	      to  any  other  value, the supplied string must be a prefix of a
	      stopped job's name; this provides	functionality analogous	to the
	      %string job identifier.
       histchars
	      The  two or three	characters which control history expansion and
	      tokenization (see	HISTORY	EXPANSION below).  The first character
	      is  the history expansion	character, the character which signals
	      the start	of a history  expansion,  normally  `!'.   The	second
	      character	 is the	quick substitution character, which is used as
	      shorthand	for re-running the previous command  entered,  substi-
	      tuting  one  string  for another in the command.	The default is
	      `^'.  The	optional third character is the	character which	 indi-
	      cates  that the remainder	of the line is a comment when found as
	      the first	character of a word, normally `#'.  The	 history  com-
	      ment character causes history substitution to be skipped for the
	      remaining	words on the line.  It does not	necessarily cause  the
	      shell parser to treat the	rest of	the line as a comment.

   Arrays
       Bash  provides one-dimensional indexed and associative array variables.
       Any variable may	be used	as an indexed array; the declare builtin  will
       explicitly  declare an array.  There is no maximum limit	on the size of
       an array, nor any requirement that members be indexed or	assigned  con-
       tiguously.   Indexed  arrays  are  referenced using integers (including
       arithmetic expressions) and are zero-based; associative arrays are ref-
       erenced using arbitrary strings.	 Unless	otherwise noted, indexed array
       indices must be non-negative integers.

       An indexed array	is created automatically if any	variable  is  assigned
       to using	the syntax name[subscript]=value.  The subscript is treated as
       an arithmetic expression	that must evaluate to a	number.	 To explicitly
       declare	an  indexed array, use declare -a name (see SHELL BUILTIN COM-
       MANDS below).  declare -a name[subscript] is also  accepted;  the  sub-
       script is ignored.

       Associative arrays are created using declare -A name.

       Attributes may be specified for an array	variable using the declare and
       readonly	builtins.  Each	attribute applies to all members of an	array.

       Arrays	are  assigned  to  using  compound  assignments	 of  the  form
       name=(value1 ...	valuen),  where	 each  value  is  of  the  form	 [sub-
       script]=string.	 Indexed array assignments do not require anything but
       string.	When assigning to indexed arrays, if the optional brackets and
       subscript  are supplied,	that index is assigned to; otherwise the index
       of the element assigned is the last index assigned to by	the  statement
       plus one.  Indexing starts at zero.

       When assigning to an associative	array, the subscript is	required.

       This  syntax is also accepted by	the declare builtin.  Individual array
       elements	may be assigned	 to  using  the	 name[subscript]=value	syntax
       introduced  above.  When	assigning to an	indexed	array, if name is sub-
       scripted	by a negative number, that number is interpreted  as  relative
       to  one	greater	 than  the  maximum index of name, so negative indices
       count back from the end of the array, and an index of -1	references the
       last element.

       Any  element  of	 an  array may be referenced using ${name[subscript]}.
       The braces are required to avoid	conflicts with pathname	expansion.  If
       subscript  is  @	 or *, the word	expands	to all members of name.	 These
       subscripts differ only when the word appears within double quotes.   If
       the word	is double-quoted, ${name[*]} expands to	a single word with the
       value of	each array member separated by the first character of the  IFS
       special variable, and ${name[@]}	expands	each element of	name to	a sep-
       arate word.  When there are no array  members,  ${name[@]}  expands  to
       nothing.	  If  the  double-quoted  expansion  occurs within a word, the
       expansion of the	first parameter	is joined with the beginning  part  of
       the  original  word,  and the expansion of the last parameter is	joined
       with the	last part of the original word.	  This	is  analogous  to  the
       expansion  of  the  special  parameters * and @ (see Special Parameters
       above).	${#name[subscript]}  expands  to  the  length  of  ${name[sub-
       script]}.   If subscript	is * or	@, the expansion is the	number of ele-
       ments in	the array.  If the subscript used to reference an  element  of
       an  indexed  array  evaluates  to a number less than zero, it is	inter-
       preted as relative to one greater than the maximum index	of the	array,
       so  negative indices count back from the	end of the array, and an index
       of -1 references	the last element.

       Referencing an array variable without a subscript is equivalent to ref-
       erencing	 the array with	a subscript of 0.  Any reference to a variable
       using a valid subscript is legal, and bash will create an array if nec-
       essary.

       An  array variable is considered	set if a subscript has been assigned a
       value.  The null	string is a valid value.

       It is possible to obtain	the keys (indices) of an array as well as  the
       values.	 ${!name[@]} and ${!name[*]} expand to the indices assigned in
       array variable name.  The treatment when	in double quotes is similar to
       the expansion of	the special parameters @ and * within double quotes.

       The  unset  builtin  is	used to	destroy	arrays.	 unset name[subscript]
       destroys	the array element at index subscript.  Negative	subscripts  to
       indexed	arrays are interpreted as described above.  Care must be taken
       to avoid	unwanted side effects caused  by  pathname  expansion.	 unset
       name, where name	is an array, or	unset name[subscript], where subscript
       is * or @, removes the entire array.

       The declare, local, and readonly	builtins each accept a	-a  option  to
       specify	an  indexed  array  and	 a -A option to	specify	an associative
       array.  If both options are supplied, -A	takes  precedence.   The  read
       builtin	accepts	 a  -a	option to assign a list	of words read from the
       standard	input to an array.  The	set and	declare	builtins display array
       values in a way that allows them	to be reused as	assignments.

EXPANSION
       Expansion is performed on the command line after	it has been split into
       words.  There are seven kinds of	expansion performed: brace  expansion,
       tilde  expansion,  parameter  and variable expansion, command substitu-
       tion, arithmetic	expansion, word	splitting, and pathname	expansion.

       The order of expansions is: brace expansion; tilde expansion, parameter
       and  variable expansion,	arithmetic expansion, and command substitution
       (done in	a left-to-right	fashion); word splitting; and pathname	expan-
       sion.

       On systems that can support it, there is	an additional expansion	avail-
       able: process substitution.  This is performed  at  the	same  time  as
       tilde,  parameter,  variable, and arithmetic expansion and command sub-
       stitution.

       After these expansions are performed, quote characters present  in  the
       original	 word  are  removed  unless  they  have	been quoted themselves
       (quote removal).

       Only brace expansion, word splitting, and pathname expansion can	change
       the  number of words of the expansion; other expansions expand a	single
       word to a single	word.  The only	exceptions to this are the  expansions
       of "$@" and "${name[@]}"	as explained above (see	PARAMETERS).

   Brace Expansion
       Brace expansion is a mechanism by which arbitrary strings may be	gener-
       ated.  This mechanism is	similar	to pathname expansion, but  the	 file-
       names generated need not	exist.	Patterns to be brace expanded take the
       form of an optional preamble, followed by either	a series of comma-sep-
       arated  strings or a sequence expression	between	a pair of braces, fol-
       lowed by	an optional postscript.	 The  preamble	is  prefixed  to  each
       string contained	within the braces, and the postscript is then appended
       to each resulting string, expanding left	to right.

       Brace expansions	may be nested.	The results of	each  expanded	string
       are  not	 sorted;  left	to  right  order  is  preserved.  For example,
       a{d,c,b}e expands into `ade ace abe'.

       A sequence expression takes the form {x..y[..incr]}, where x and	y  are
       either  integers	or single characters, and incr,	an optional increment,
       is an integer.  When integers are supplied, the expression  expands  to
       each  number between x and y, inclusive.	 Supplied integers may be pre-
       fixed with 0 to force each term to have the same	width.	When either  x
       or  y  begins  with  a  zero, the shell attempts	to force all generated
       terms to	contain	the same number	of digits, zero-padding	 where	neces-
       sary.   When  characters	 are  supplied,	the expression expands to each
       character lexicographically between  x  and  y,	inclusive,  using  the
       default	C  locale.   Note  that	both x and y must be of	the same type.
       When the	increment is supplied, it is used as  the  difference  between
       each term.  The default increment is 1 or -1 as appropriate.

       Brace expansion is performed before any other expansions, and any char-
       acters special to other expansions are preserved	in the result.	It  is
       strictly	 textual.  Bash	does not apply any syntactic interpretation to
       the context of the expansion or the text	between	the braces.

       A correctly-formed brace	expansion must contain	unquoted  opening  and
       closing	braces,	 and  at  least	one unquoted comma or a	valid sequence
       expression.  Any	incorrectly formed brace expansion is left  unchanged.
       A { or ,	may be quoted with a backslash to prevent its being considered
       part of a brace expression.  To avoid conflicts with  parameter	expan-
       sion, the string	${ is not considered eligible for brace	expansion.

       This construct is typically used	as shorthand when the common prefix of
       the strings to be generated is longer than in the above example:

	      mkdir /usr/local/src/bash/{old,new,dist,bugs}
       or
	      chown root /usr/{ucb/{ex,edit},lib/{ex?.?*,how_ex}}

       Brace expansion introduces a  slight  incompatibility  with  historical
       versions	 of sh.	 sh does not treat opening or closing braces specially
       when they appear	as part	of a word, and preserves them in  the  output.
       Bash  removes  braces  from  words as a consequence of brace expansion.
       For example, a word entered to sh as file{1,2} appears  identically  in
       the  output.  The same word is output as	file1 file2 after expansion by
       bash.  If strict	compatibility with sh is desired, start	bash with  the
       +B option or disable brace expansion with the +B	option to the set com-
       mand (see SHELL BUILTIN COMMANDS	below).

   Tilde Expansion
       If a word begins	with an	unquoted tilde character  (`~'),  all  of  the
       characters  preceding  the  first unquoted slash	(or all	characters, if
       there is	no unquoted slash) are considered a tilde-prefix.  If none  of
       the  characters	in  the	tilde-prefix are quoted, the characters	in the
       tilde-prefix following the tilde	are treated as a possible login	 name.
       If  this	 login name is the null	string,	the tilde is replaced with the
       value of	the shell parameter HOME.  If HOME is unset, the  home	direc-
       tory  of	 the  user executing the shell is substituted instead.	Other-
       wise, the tilde-prefix is replaced with the home	 directory  associated
       with the	specified login	name.

       If  the	tilde-prefix  is  a  `~+', the value of	the shell variable PWD
       replaces	the tilde-prefix.  If the tilde-prefix is a `~-', the value of
       the  shell variable OLDPWD, if it is set, is substituted.  If the char-
       acters following	the tilde in the tilde-prefix consist of a  number  N,
       optionally  prefixed  by	 a  `+'	or a `-', the tilde-prefix is replaced
       with the	corresponding element from the directory stack,	as it would be
       displayed by the	dirs builtin invoked with the tilde-prefix as an argu-
       ment.  If the characters	following the tilde in the  tilde-prefix  con-
       sist of a number	without	a leading `+' or `-', `+' is assumed.

       If the login name is invalid, or	the tilde expansion fails, the word is
       unchanged.

       Each variable assignment	is checked for unquoted	tilde-prefixes immedi-
       ately following a : or the first	=.  In these cases, tilde expansion is
       also performed.	Consequently, one may use  filenames  with  tildes  in
       assignments  to	PATH,  MAILPATH, and CDPATH, and the shell assigns the
       expanded	value.

   Parameter Expansion
       The `$' character introduces parameter expansion, command substitution,
       or  arithmetic  expansion.  The parameter name or symbol	to be expanded
       may be enclosed in braces, which	are optional but serve to protect  the
       variable	 to be expanded	from characters	immediately following it which
       could be	interpreted as part of the name.

       When braces are used, the matching ending brace is the  first  `}'  not
       escaped	by  a  backslash  or within a quoted string, and not within an
       embedded	 arithmetic  expansion,	 command  substitution,	 or  parameter
       expansion.

       ${parameter}
	      The  value of parameter is substituted.  The braces are required
	      when parameter is	a positional  parameter	 with  more  than  one
	      digit, or	when parameter is followed by a	character which	is not
	      to be interpreted	as part	of its name.  The parameter is a shell
	      parameter	 as  described above PARAMETERS) or an array reference
	      (Arrays).

       If the first character of parameter is an exclamation  point  (!),  and
       parameter  is not a nameref, it introduces a level of variable indirec-
       tion.  Bash uses	the value of the variable  formed  from	 the  rest  of
       parameter  as  the name of the variable;	this variable is then expanded
       and that	value is used in the rest of the substitution, rather than the
       value  of  parameter  itself.  This is known as indirect	expansion.  If
       parameter is a nameref, this expands to the name	of the variable	refer-
       enced  by  parameter instead of performing the complete indirect	expan-
       sion.  The exceptions to	this are the  expansions  of  ${!prefix*}  and
       ${!name[@]}  described  below.	The exclamation	point must immediately
       follow the left brace in	order to introduce indirection.

       In each of the cases below, word	is subject to tilde expansion, parame-
       ter expansion, command substitution, and	arithmetic expansion.

       When  not  performing  substring	 expansion, using the forms documented
       below (e.g., :-), bash tests for	a parameter that  is  unset  or	 null.
       Omitting	 the  colon  results  in  a  test only for a parameter that is
       unset.

       ${parameter:-word}
	      Use Default Values.  If parameter	is unset or null,  the	expan-
	      sion  of word is substituted.  Otherwise,	the value of parameter
	      is substituted.
       ${parameter:=word}
	      Assign Default Values.  If  parameter  is	 unset	or  null,  the
	      expansion	of word	is assigned to parameter.  The value of	param-
	      eter is then substituted.	  Positional  parameters  and  special
	      parameters may not be assigned to	in this	way.
       ${parameter:?word}
	      Display  Error if	Null or	Unset.	If parameter is	null or	unset,
	      the expansion of word (or	a message to that effect  if  word  is
	      not  present) is written to the standard error and the shell, if
	      it is not	interactive, exits.  Otherwise,	the value of parameter
	      is substituted.
       ${parameter:+word}
	      Use  Alternate Value.  If	parameter is null or unset, nothing is
	      substituted, otherwise the expansion of word is substituted.
       ${parameter:offset}
       ${parameter:offset:length}
	      Substring	Expansion.  Expands to up to length characters of  the
	      value  of	 parameter starting at the character specified by off-
	      set.  If parameter is @, an indexed array	subscripted by @ or *,
	      or  an  associative  array name, the results differ as described
	      below.  If length	is omitted, expands to the  substring  of  the
	      value of parameter starting at the character specified by	offset
	      and extending to the end of the value.  length  and  offset  are
	      arithmetic expressions (see ARITHMETIC EVALUATION	below).

	      If  offset  evaluates  to	 a number less than zero, the value is
	      used as an offset	in characters from the end  of	the  value  of
	      parameter.   If  length evaluates	to a number less than zero, it
	      is interpreted as	an offset in characters	from the  end  of  the
	      value  of	 parameter rather than a number	of characters, and the
	      expansion	is the characters  between  offset  and	 that  result.
	      Note  that a negative offset must	be separated from the colon by
	      at least one space to avoid being	confused with  the  :-	expan-
	      sion.

	      If  parameter  is	 @, the	result is length positional parameters
	      beginning	at offset.  A negative offset is taken relative	to one
	      greater  than the	greatest positional parameter, so an offset of
	      -1 evaluates to the last positional parameter.  It is an	expan-
	      sion error if length evaluates to	a number less than zero.

	      If parameter is an indexed array name subscripted	by @ or	*, the
	      result is	 the  length  members  of  the	array  beginning  with
	      ${parameter[offset]}.   A	 negative  offset is taken relative to
	      one greater than the maximum index of the	specified  array.   It
	      is  an expansion error if	length evaluates to a number less than
	      zero.

	      Substring	expansion applied to  an  associative  array  produces
	      undefined	results.

	      Substring	 indexing  is zero-based unless	the positional parame-
	      ters are used, in	 which	case  the  indexing  starts  at	 1  by
	      default.	 If  offset  is	 0,  and the positional	parameters are
	      used, $0 is prefixed to the list.

       ${!prefix*}
       ${!prefix@}
	      Names matching prefix.  Expands to the names of variables	 whose
	      names begin with prefix, separated by the	first character	of the
	      IFS special variable.  When @ is used and	the expansion  appears
	      within  double  quotes, each variable name expands to a separate
	      word.

       ${!name[@]}
       ${!name[*]}
	      List of array keys.  If name is an array	variable,  expands  to
	      the  list	 of array indices (keys) assigned in name.  If name is
	      not an array, expands to 0 if name is set	 and  null  otherwise.
	      When  @  is used and the expansion appears within	double quotes,
	      each key expands to a separate word.

       ${#parameter}
	      Parameter	length.	 The length in	characters  of	the  value  of
	      parameter	 is  substituted.   If	parameter is * or @, the value
	      substituted is the number	of positional parameters.  If  parame-
	      ter  is  an  array name subscripted by * or @, the value substi-
	      tuted is the number of elements in the array.  If	 parameter  is
	      an  indexed  array  name	subscripted by a negative number, that
	      number is	interpreted as relative	to one greater than the	 maxi-
	      mum  index of parameter, so negative indices count back from the
	      end of the array,	and an index of	-1 references  the  last  ele-
	      ment.

       ${parameter#word}
       ${parameter##word}
	      Remove matching prefix pattern.  The word	is expanded to produce
	      a	pattern	just as	in pathname expansion.	If the pattern matches
	      the  beginning of	the value of parameter,	then the result	of the
	      expansion	is the expanded	value of parameter with	 the  shortest
	      matching	pattern	 (the ``#'' case) or the longest matching pat-
	      tern (the	``##'' case) deleted.  If parameter is	@  or  *,  the
	      pattern  removal operation is applied to each positional parame-
	      ter in turn, and the expansion is	the resultant list.  If	param-
	      eter  is	an array variable subscripted with @ or	*, the pattern
	      removal operation	is applied to each  member  of	the  array  in
	      turn, and	the expansion is the resultant list.

       ${parameter%word}
       ${parameter%%word}
	      Remove matching suffix pattern.  The word	is expanded to produce
	      a	pattern	just as	in pathname expansion.	If the pattern matches
	      a	 trailing portion of the expanded value	of parameter, then the
	      result of	the expansion is the expanded value of parameter  with
	      the  shortest  matching  pattern (the ``%'' case)	or the longest
	      matching pattern (the ``%%'' case) deleted.  If parameter	 is  @
	      or  *,  the  pattern  removal operation is applied to each posi-
	      tional parameter in turn,	and the	 expansion  is	the  resultant
	      list.   If  parameter is an array	variable subscripted with @ or
	      *, the pattern removal operation is applied to  each  member  of
	      the array	in turn, and the expansion is the resultant list.

       ${parameter/pattern/string}
	      Pattern substitution.  The pattern is expanded to	produce	a pat-
	      tern just	as in pathname expansion.  Parameter is	 expanded  and
	      the  longest match of pattern against its	value is replaced with
	      string.  If pattern begins with /, all matches  of  pattern  are
	      replaced	 with  string.	 Normally  only	 the  first  match  is
	      replaced.	 If pattern begins with	#, it must match at the	begin-
	      ning of the expanded value of parameter.	If pattern begins with
	      %, it must match at the end of the expanded value	of  parameter.
	      If string	is null, matches of pattern are	deleted	and the	/ fol-
	      lowing pattern may be omitted.  If the nocasematch shell	option
	      is enabled, the match is performed without regard	to the case of
	      alphabetic characters.  If parameter is @	or *, the substitution
	      operation	 is  applied to	each positional	parameter in turn, and
	      the expansion is the resultant list.  If parameter is  an	 array
	      variable	subscripted with @ or *, the substitution operation is
	      applied to each member of	the array in turn, and	the  expansion
	      is the resultant list.

       ${parameter^pattern}
       ${parameter^^pattern}
       ${parameter,pattern}
       ${parameter,,pattern}
	      Case  modification.   This expansion modifies the	case of	alpha-
	      betic characters in parameter.  The pattern is expanded to  pro-
	      duce a pattern just as in	pathname expansion.  Each character in
	      the expanded value of parameter is tested	against	pattern,  and,
	      if  it  matches the pattern, its case is converted.  The pattern
	      should not attempt to match more	than  one  character.	The  ^
	      operator	converts  lowercase letters matching pattern to	upper-
	      case; the	, operator converts matching uppercase letters to low-
	      ercase.  The ^^ and ,, expansions	convert	each matched character
	      in the expanded value; the ^ and , expansions match and  convert
	      only  the	 first character in the	expanded value.	 If pattern is
	      omitted, it is treated like a ?, which matches every  character.
	      If  parameter  is	 @  or	*,  the	case modification operation is
	      applied to each positional parameter in turn, and	the  expansion
	      is  the  resultant list.	If parameter is	an array variable sub-
	      scripted with @ or *, the	case modification operation is applied
	      to  each	member	of the array in	turn, and the expansion	is the
	      resultant	list.

       ${parameter@operator}
	      Parameter	transformation.	 The expansion is either a transforma-
	      tion  of	the  value of parameter	or information about parameter
	      itself, depending	on the value of	operator.  Each	operator is  a
	      single letter:

	      Q	     The  expansion is a string	that is	the value of parameter
		     quoted in a format	that can be reused as input.
	      E	     The expansion is a	string that is the value of  parameter
		     with  backslash  escape  sequences	 expanded  as with the
		     $'...' quoting mechansim.
	      P	     The expansion is a	string that is the result of expanding
		     the value of parameter as if it were a prompt string (see
		     PROMPTING below).
	      A	     The expansion is a	string in the form  of	an  assignment
		     statement	or  declare  command  that, if evaluated, will
		     recreate parameter	with its attributes and	value.
	      a	     The expansion is a	string consisting of flag values  rep-
		     resenting parameter's attributes.

	      If  parameter  is	@ or *,	the operation is applied to each posi-
	      tional parameter in turn,	and the	 expansion  is	the  resultant
	      list.   If  parameter is an array	variable subscripted with @ or
	      *, the case modification operation is applied to each member  of
	      the array	in turn, and the expansion is the resultant list.

	      The  result  of  the  expansion is subject to word splitting and
	      pathname expansion as described below.

   Command Substitution
       Command substitution allows the output of a command to replace the com-
       mand name.  There are two forms:

	      $(command)
       or
	      `command`

       Bash performs the expansion by executing	command	in a subshell environ-
       ment and	replacing the command substitution with	the standard output of
       the command, with any trailing newlines deleted.	 Embedded newlines are
       not deleted, but	they may be removed during word	splitting.   The  com-
       mand  substitution  $(cat  file)	 can be	replaced by the	equivalent but
       faster $(< file).

       When the	old-style backquote form of substitution  is  used,  backslash
       retains	its  literal  meaning except when followed by $, `, or \.  The
       first backquote not preceded by a backslash terminates the command sub-
       stitution.   When using the $(command) form, all	characters between the
       parentheses make	up the command;	none are treated specially.

       Command substitutions may be nested.  To	nest when using	the backquoted
       form, escape the	inner backquotes with backslashes.

       If  the	substitution  appears within double quotes, word splitting and
       pathname	expansion are not performed on the results.

   Arithmetic Expansion
       Arithmetic expansion allows the evaluation of an	arithmetic  expression
       and  the	 substitution of the result.  The format for arithmetic	expan-
       sion is:

	      $((expression))

       The expression is treated as if it were within  double  quotes,	but  a
       double  quote  inside  the  parentheses	is not treated specially.  All
       tokens in the expression	undergo	parameter and variable expansion, com-
       mand  substitution,  and	 quote	removal.  The result is	treated	as the
       arithmetic expression to	be evaluated.  Arithmetic  expansions  may  be
       nested.

       The  evaluation	is performed according to the rules listed below under
       ARITHMETIC EVALUATION.  If expression is	invalid, bash prints a message
       indicating failure and no substitution occurs.

   Process Substitution
       Process	substitution allows a process's	input or output	to be referred
       to using	a filename.  It	takes the form of  <(list)  or	>(list).   The
       process	list is	run asynchronously, and	its input or output appears as
       a filename.  This filename is passed as an argument to the current com-
       mand  as	 the  result  of  the expansion.  If the >(list) form is used,
       writing to the file will	provide	input for list.	 If the	 <(list)  form
       is  used,  the  file passed as an argument should be read to obtain the
       output of list.	Process	substitution is	supported on systems that sup-
       port named pipes	(FIFOs)	or the /dev/fd method of naming	open files.

       When  available,	 process substitution is performed simultaneously with
       parameter and variable expansion, command substitution, and  arithmetic
       expansion.

   Word	Splitting
       The  shell  scans the results of	parameter expansion, command substitu-
       tion, and arithmetic expansion that did not occur within	double	quotes
       for word	splitting.

       The  shell  treats each character of IFS	as a delimiter,	and splits the
       results of the other expansions into words using	 these	characters  as
       field   terminators.   If  IFS  is  unset,  or  its  value  is  exactly
       <space><tab><newline>, the default, then	sequences of  <space>,	<tab>,
       and  <newline>  at the beginning	and end	of the results of the previous
       expansions are ignored, and any sequence	of IFS characters not  at  the
       beginning  or  end  serves  to delimit words.  If IFS has a value other
       than the	default, then sequences	of the	whitespace  characters	space,
       tab,  and  newline are ignored at the beginning and end of the word, as
       long as the whitespace character	is in the value	of IFS (an IFS	white-
       space  character).   Any	 character  in IFS that	is not IFS whitespace,
       along with any adjacent IFS whitespace characters, delimits a field.  A
       sequence	 of  IFS whitespace characters is also treated as a delimiter.
       If the value of IFS is null, no word splitting occurs.

       Explicit	null arguments ("" or '') are retained and passed to  commands
       as empty	strings.  Unquoted implicit null arguments, resulting from the
       expansion of parameters that have no values, are	removed.  If a parame-
       ter  with  no  value  is	expanded within	double quotes, a null argument
       results and is retained and passed to a command	as  an	empty  string.
       When  a	quoted null argument appears as	part of	a word whose expansion
       is non-null, the	null argument is removed.   That  is,  the  word  -d''
       becomes -d after	word splitting and null	argument removal.

       Note that if no expansion occurs, no splitting is performed.

   Pathname Expansion
       After  word  splitting,	unless	the -f option has been set, bash scans
       each word for the characters *, ?, and [.  If one of  these  characters
       appears,	 then  the word	is regarded as a pattern, and replaced with an
       alphabetically sorted list of filenames matching	the pattern (see  Pat-
       tern  Matching  below).	 If  no	 matching filenames are	found, and the
       shell option nullglob is	not enabled, the word is left  unchanged.   If
       the  nullglob  option  is  set,	and  no	matches	are found, the word is
       removed.	 If the	failglob shell option  is  set,	 and  no  matches  are
       found, an error message is printed and the command is not executed.  If
       the shell option	nocaseglob is enabled, the match is performed  without
       regard  to  the	case of	alphabetic characters.	When a pattern is used
       for pathname expansion, the character ``.''  at the start of a name  or
       immediately  following  a  slash	must be	matched	explicitly, unless the
       shell option dotglob is set.  When matching a pathname, the slash char-
       acter  must  always  be	matched	explicitly.  In	other cases, the ``.''
       character is not	treated	specially.  See	the description	of shopt below
       under SHELL BUILTIN COMMANDS for	a description of the nocaseglob, null-
       glob, failglob, and dotglob shell options.

       The GLOBIGNORE shell variable may be used to restrict the set of	 file-
       names matching a	pattern.  If GLOBIGNORE	is set,	each matching filename
       that also matches one of	the patterns in	GLOBIGNORE is removed from the
       list of matches.	 If the	nocaseglob option is set, the matching against
       the patterns in GLOBIGNORE is performed without regard  to  case.   The
       filenames  ``.''	 and ``..''  are always	ignored	when GLOBIGNORE	is set
       and not null.  However, setting GLOBIGNORE to a non-null	value has  the
       effect  of  enabling  the  dotglob shell	option,	so all other filenames
       beginning with a	``.''  will match.  To get the old behavior of	ignor-
       ing  filenames beginning	with a ``.'', make ``.*''  one of the patterns
       in GLOBIGNORE.  The dotglob  option  is	disabled  when	GLOBIGNORE  is
       unset.	The  pattern  matching honors the setting of the extglob shell
       option.

       Pattern Matching

       Any character that appears in a pattern,	other than the special pattern
       characters  described below, matches itself.  The NUL character may not
       occur in	a pattern.  A backslash	escapes	the following  character;  the
       escaping	 backslash  is	discarded  when	matching.  The special pattern
       characters must be quoted if they are to	be matched literally.

       The special pattern characters have the following meanings:

	      *	     Matches any string, including the null string.  When  the
		     globstar  shell  option  is  enabled,  and	* is used in a
		     pathname expansion	context, two adjacent  *s  used	 as  a
		     single  pattern  will  match  all	files and zero or more
		     directories and subdirectories.  If followed by a /,  two
		     adjacent  *s  will	match only directories and subdirecto-
		     ries.
	      ?	     Matches any single	character.
	      [...]  Matches any one of	the enclosed characters.   A  pair  of
		     characters	 separated by a	hyphen denotes a range expres-
		     sion; any character that falls between those two  charac-
		     ters,  inclusive,	using  the  current locale's collating
		     sequence and character set, is  matched.	If  the	 first
		     character following the [ is a !  or a ^ then any charac-
		     ter not enclosed is matched.  The sorting order of	 char-
		     acters  in	range expressions is determined	by the current
		     locale and	the values of the LC_COLLATE or	 LC_ALL	 shell
		     variables,	if set.	 To obtain the traditional interpreta-
		     tion of range expressions,	where [a-d] is	equivalent  to
		     [abcd],  set  value of the	LC_ALL shell variable to C, or
		     enable the	globasciiranges	shell  option.	 A  -  may  be
		     matched by	including it as	the first or last character in
		     the set.  A ] may be matched by including it as the first
		     character in the set.

		     Within  [ and ], character	classes	can be specified using
		     the syntax	[:class:], where class is one of the following
		     classes defined in	the POSIX standard:
		     alnum  alpha  ascii  blank	 cntrl digit graph lower print
		     punct space upper word xdigit
		     A character class matches any character belonging to that
		     class.  The word character	class matches letters, digits,
		     and the character _.

		     Within [ and ], an	equivalence  class  can	 be  specified
		     using the syntax [=c=], which matches all characters with
		     the same collation	weight	(as  defined  by  the  current
		     locale) as	the character c.

		     Within [ and ], the syntax	[.symbol.] matches the collat-
		     ing symbol	symbol.

       If the extglob shell option is enabled using the	shopt builtin, several
       extended	 pattern  matching operators are recognized.  In the following
       description, a pattern-list is a	list of	one or more patterns separated
       by a |.	Composite patterns may be formed using one or more of the fol-
       lowing sub-patterns:

	      ?(pattern-list)
		     Matches zero or one occurrence of the given patterns
	      *(pattern-list)
		     Matches zero or more occurrences of the given patterns
	      +(pattern-list)
		     Matches one or more occurrences of	the given patterns
	      @(pattern-list)
		     Matches one of the	given patterns
	      !(pattern-list)
		     Matches anything except one of the	given patterns

   Quote Removal
       After the preceding expansions, all unquoted occurrences	of the charac-
       ters  \,	 ', and	" that did not result from one of the above expansions
       are removed.

REDIRECTION
       Before a	command	is executed, its input and output  may	be  redirected
       using  a	special	notation interpreted by	the shell.  Redirection	allows
       commands' file handles to be duplicated,	opened,	closed,	made to	 refer
       to different files, and can change the files the	command	reads from and
       writes to.  Redirection may also	be used	to modify file handles in  the
       current	shell execution	environment.  The following redirection	opera-
       tors may	precede	or appear anywhere within a simple command or may fol-
       low  a  command.	  Redirections are processed in	the order they appear,
       from left to right.

       Each redirection	that may be preceded by	a file descriptor  number  may
       instead be preceded by a	word of	the form {varname}.  In	this case, for
       each redirection	operator except	>&- and	<&-, the shell will allocate a
       file  descriptor	 greater than or equal to 10 and assign	it to varname.
       If >&- or <&- is	preceded by {varname}, the value  of  varname  defines
       the file	descriptor to close.

       In  the	following descriptions,	if the file descriptor number is omit-
       ted, and	the first character of the redirection operator	is <, the  re-
       direction  refers  to  the  standard input (file	descriptor 0).	If the
       first character of the  redirection  operator  is  >,  the  redirection
       refers to the standard output (file descriptor 1).

       The  word  following the	redirection operator in	the following descrip-
       tions, unless otherwise noted, is subjected to brace  expansion,	 tilde
       expansion,  parameter  and  variable  expansion,	 command substitution,
       arithmetic expansion,  quote  removal,  pathname	 expansion,  and  word
       splitting.  If it expands to more than one word,	bash reports an	error.

       Note that the order of redirections is significant.  For	 example,  the
       command

	      ls > dirlist 2>&1

       directs	both  standard	output and standard error to the file dirlist,
       while the command

	      ls 2>&1 >	dirlist

       directs only the	standard output	to file	dirlist, because the  standard
       error  was duplicated from the standard output before the standard out-
       put was redirected to dirlist.

       Bash handles several filenames specially	when they are used in redirec-
       tions, as described in the following table.  If the operating system on
       which bash is running provides these special files, bash	will use them;
       otherwise  it  will emulate them	internally with	the behavior described
       below.

	      /dev/fd/fd
		     If	fd is a	valid integer, file descriptor	fd  is	dupli-
		     cated.
	      /dev/stdin
		     File descriptor 0 is duplicated.
	      /dev/stdout
		     File descriptor 1 is duplicated.
	      /dev/stderr
		     File descriptor 2 is duplicated.
	      /dev/tcp/host/port
		     If	host is	a valid	hostname or Internet address, and port
		     is	an integer port	number or service name,	bash  attempts
		     to	open the corresponding TCP socket.
	      /dev/udp/host/port
		     If	host is	a valid	hostname or Internet address, and port
		     is	an integer port	number or service name,	bash  attempts
		     to	open the corresponding UDP socket.

       A failure to open or create a file causes the redirection to fail.

       Redirections  using file	descriptors greater than 9 should be used with
       care, as	they may conflict with file descriptors	the shell uses	inter-
       nally.

   Redirecting Input
       Redirection of input causes the file whose name results from the	expan-
       sion of word to be opened for reading on	 file  descriptor  n,  or  the
       standard	input (file descriptor 0) if n is not specified.

       The general format for redirecting input	is:

	      [n]<word

   Redirecting Output
       Redirection  of	output	causes	the  file  whose name results from the
       expansion of word to be opened for writing on file descriptor n,	or the
       standard	output (file descriptor	1) if n	is not specified.  If the file
       does not	exist it is created; if	it does	exist it is truncated to  zero
       size.

       The general format for redirecting output is:

	      [n]>word

       If  the	redirection operator is	>, and the noclobber option to the set
       builtin has been	enabled, the redirection will fail if the  file	 whose
       name  results  from the expansion of word exists	and is a regular file.
       If the redirection operator is >|, or the redirection operator is > and
       the noclobber option to the set builtin command is not enabled, the re-
       direction is attempted even if the file named by	word exists.

   Appending Redirected	Output
       Redirection of output in	 this  fashion	causes	the  file  whose  name
       results	from  the expansion of word to be opened for appending on file
       descriptor n, or	the standard output (file descriptor 1)	if  n  is  not
       specified.  If the file does not	exist it is created.

       The general format for appending	output is:

	      [n]>>word

   Redirecting Standard	Output and Standard Error
       This  construct allows both the standard	output (file descriptor	1) and
       the standard error output (file descriptor 2) to	be redirected  to  the
       file whose name is the expansion	of word.

       There  are  two	formats	 for  redirecting standard output and standard
       error:

	      &>word
       and
	      >&word

       Of the two forms, the first is preferred.  This is semantically equiva-
       lent to

	      >word 2>&1

       When  using  the	second form, word may not expand to a number or	-.  If
       it does,	 other	redirection  operators	apply  (see  Duplicating  File
       Descriptors below) for compatibility reasons.

   Appending Standard Output and Standard Error
       This  construct allows both the standard	output (file descriptor	1) and
       the standard error output (file descriptor 2) to	 be  appended  to  the
       file whose name is the expansion	of word.

       The format for appending	standard output	and standard error is:

	      &>>word

       This is semantically equivalent to

	      >>word 2>&1

       (see Duplicating	File Descriptors below).

   Here	Documents
       This  type  of  redirection  instructs the shell	to read	input from the
       current source until a line containing only delimiter (with no trailing
       blanks)	is seen.  All of the lines read	up to that point are then used
       as the standard input (or file descriptor n if n	is  specified)	for  a
       command.

       The format of here-documents is:

	      [n]<<[-]word
		      here-document
	      delimiter

       No  parameter  and variable expansion, command substitution, arithmetic
       expansion, or pathname expansion	is performed on	word.  If any part  of
       word  is	 quoted, the delimiter is the result of	quote removal on word,
       and the lines in	the  here-document  are	 not  expanded.	  If  word  is
       unquoted,  all  lines  of  the here-document are	subjected to parameter
       expansion, command substitution,	and arithmetic expansion, the  charac-
       ter  sequence  \<newline>  is  ignored, and \ must be used to quote the
       characters \, $,	and `.

       If the redirection operator is <<-, then	all leading tab	characters are
       stripped	 from  input  lines  and  the line containing delimiter.  This
       allows here-documents within shell scripts to be	indented in a  natural
       fashion.

   Here	Strings
       A variant of here documents, the	format is:

	      [n]<<<word

       The  word  undergoes  brace  expansion,	tilde expansion, parameter and
       variable	expansion, command  substitution,  arithmetic  expansion,  and
       quote  removal.	 Pathname  expansion  and  word	splitting are not per-
       formed.	The result is supplied as a  single  string,  with  a  newline
       appended, to the	command	on its standard	input (or file descriptor n if
       n is specified).

   Duplicating File Descriptors
       The redirection operator

	      [n]<&word

       is used to duplicate input file descriptors.  If	word expands to	one or
       more  digits,  the file descriptor denoted by n is made to be a copy of
       that file descriptor.  If the digits in word  do	 not  specify  a  file
       descriptor  open	for input, a redirection error occurs.	If word	evalu-
       ates to -, file descriptor n is closed.	If n  is  not  specified,  the
       standard	input (file descriptor 0) is used.

       The operator

	      [n]>&word

       is  used	 similarly  to duplicate output	file descriptors.  If n	is not
       specified, the standard output (file descriptor 1)  is  used.   If  the
       digits  in word do not specify a	file descriptor	open for output, a re-
       direction error occurs.	If word	evaluates to -,	file descriptor	 n  is
       closed.	 As  a special case, if	n is omitted, and word does not	expand
       to one or more digits or	-, the standard	output and standard error  are
       redirected as described previously.

   Moving File Descriptors
       The redirection operator

	      [n]<&digit-

       moves  the  file	descriptor digit to file descriptor n, or the standard
       input (file descriptor 0) if n is not specified.	 digit is closed after
       being duplicated	to n.

       Similarly, the redirection operator

	      [n]>&digit-

       moves  the  file	descriptor digit to file descriptor n, or the standard
       output (file descriptor 1) if n is not specified.

   Opening File	Descriptors for	Reading	and Writing
       The redirection operator

	      [n]<>word

       causes the file whose name is the expansion of word to  be  opened  for
       both  reading and writing on file descriptor n, or on file descriptor 0
       if n is not specified.  If the file does	not exist, it is created.

ALIASES
       Aliases allow a string to be substituted	for a word when	it is used  as
       the  first  word	 of  a	simple command.	 The shell maintains a list of
       aliases that may	be set and unset with the alias	 and  unalias  builtin
       commands	 (see  SHELL  BUILTIN COMMANDS below).	The first word of each
       simple command, if unquoted, is checked to see if it has	an alias.   If
       so,  that word is replaced by the text of the alias.  The characters /,
       $, `, and = and any of the shell	metacharacters or  quoting  characters
       listed above may	not appear in an alias name.  The replacement text may
       contain any valid shell input,  including  shell	 metacharacters.   The
       first  word  of	the replacement	text is	tested for aliases, but	a word
       that is identical to an alias being expanded is not expanded  a	second
       time.   This  means  that  one may alias	ls to ls -F, for instance, and
       bash does not try to recursively	expand the replacement text.   If  the
       last  character	of  the	 alias value is	a blank, then the next command
       word following the alias	is also	checked	for alias expansion.

       Aliases are created and listed with the alias command, and removed with
       the unalias command.

       There  is no mechanism for using	arguments in the replacement text.  If
       arguments are needed, a shell function should be	 used  (see  FUNCTIONS
       below).

       Aliases	are not	expanded when the shell	is not interactive, unless the
       expand_aliases shell option is set using	shopt (see the description  of
       shopt under SHELL BUILTIN COMMANDS below).

       The  rules  concerning  the  definition and use of aliases are somewhat
       confusing.  Bash	always reads at	 least	one  complete  line  of	 input
       before  executing  any  of  the	commands  on  that  line.  Aliases are
       expanded	when a command is read,	not when it is	executed.   Therefore,
       an  alias definition appearing on the same line as another command does
       not take	effect until the next line of input  is	 read.	 The  commands
       following the alias definition on that line are not affected by the new
       alias.  This behavior is	also an	issue  when  functions	are  executed.
       Aliases	are  expanded when a function definition is read, not when the
       function	is executed, because a function	definition is  itself  a  com-
       mand.   As  a consequence, aliases defined in a function	are not	avail-
       able until after	that function is executed.  To	be  safe,  always  put
       alias  definitions on a separate	line, and do not use alias in compound
       commands.

       For almost every	purpose, aliases are superseded	by shell functions.

FUNCTIONS
       A shell function, defined  as  described	 above	under  SHELL  GRAMMAR,
       stores  a  series  of commands for later	execution.  When the name of a
       shell function is used as a simple command name,	the list  of  commands
       associated with that function name is executed.	Functions are executed
       in the context of the current shell;  no	 new  process  is  created  to
       interpret  them	(contrast  this	with the execution of a	shell script).
       When a function is executed, the	arguments to the function  become  the
       positional parameters during its	execution.  The	special	parameter # is
       updated to reflect the change.  Special parameter 0 is unchanged.   The
       first  element of the FUNCNAME variable is set to the name of the func-
       tion while the function is executing.

       All other aspects of the	 shell	execution  environment	are  identical
       between	a function and its caller with these exceptions: the DEBUG and
       RETURN traps (see the description  of  the  trap	 builtin  under	 SHELL
       BUILTIN	COMMANDS below)	are not	inherited unless the function has been
       given the trace attribute (see the description of the  declare  builtin
       below)  or  the -o functrace shell option has been enabled with the set
       builtin (in which case all  functions  inherit  the  DEBUG  and	RETURN
       traps),	and the	ERR trap is not	inherited unless the -o	errtrace shell
       option has been enabled.

       Variables local to the function may be declared with the	local  builtin
       command.	 Ordinarily, variables and their values	are shared between the
       function	and its	caller.

       The FUNCNEST variable, if set  to  a  numeric  value  greater  than  0,
       defines	a  maximum  function nesting level.  Function invocations that
       exceed the limit	cause the entire command to abort.

       If the builtin command return is	executed in a function,	 the  function
       completes  and  execution resumes with the next command after the func-
       tion call.  Any command associated with the  RETURN  trap  is  executed
       before execution	resumes.  When a function completes, the values	of the
       positional parameters and the special parameter # are restored  to  the
       values they had prior to	the function's execution.

       Function	 names and definitions may be listed with the -f option	to the
       declare or typeset builtin commands.  The -F option to declare or type-
       set  will  list the function names only (and optionally the source file
       and line	number,	if the extdebug	shell option is	 enabled).   Functions
       may  be exported	so that	subshells automatically	have them defined with
       the -f option to	the export builtin.   A	 function  definition  may  be
       deleted	using  the  -f	option	to the unset builtin.  Note that shell
       functions and variables with the	same name may result in	multiple iden-
       tically-named  entries  in  the environment passed to the shell's chil-
       dren.  Care should be taken in cases where this may cause a problem.

       Functions may be	recursive.  The	FUNCNEST variable may be used to limit
       the  depth  of the function call	stack and restrict the number of func-
       tion invocations.  By default, no limit is imposed  on  the  number  of
       recursive calls.

ARITHMETIC EVALUATION
       The  shell allows arithmetic expressions	to be evaluated, under certain
       circumstances (see the let and declare builtin commands,	 the  ((  com-
       pound command, and Arithmetic Expansion).  Evaluation is	done in	fixed-
       width integers with no check for	overflow,  though  division  by	 0  is
       trapped	and  flagged as	an error.  The operators and their precedence,
       associativity, and values are the same as in the	C language.  The  fol-
       lowing  list  of	 operators  is grouped into levels of equal-precedence
       operators.  The levels are listed in order of decreasing	precedence.

       id++ id--
	      variable post-increment and post-decrement
       ++id --id
	      variable pre-increment and pre-decrement
       - +    unary minus and plus
       ! ~    logical and bitwise negation
       **     exponentiation
       * / %  multiplication, division,	remainder
       + -    addition,	subtraction
       << >>  left and right bitwise shifts
       <= >= < >
	      comparison
       == !=  equality and inequality
       &      bitwise AND
       ^      bitwise exclusive	OR
       |      bitwise OR
       &&     logical AND
       ||     logical OR
       expr?expr:expr
	      conditional operator
       = *= /= %= += -=	<<= >>=	&= ^= |=
	      assignment
       expr1 , expr2
	      comma

       Shell variables are allowed as operands;	parameter  expansion  is  per-
       formed before the expression is evaluated.  Within an expression, shell
       variables may also be referenced	by name	without	 using	the  parameter
       expansion  syntax.  A shell variable that is null or unset evaluates to
       0 when referenced by name without using the parameter expansion syntax.
       The  value  of a	variable is evaluated as an arithmetic expression when
       it is referenced, or when a variable which has been given  the  integer
       attribute using declare -i is assigned a	value.	A null value evaluates
       to 0.  A	shell variable need not	have its integer attribute  turned  on
       to be used in an	expression.

       Constants with a	leading	0 are interpreted as octal numbers.  A leading
       0x or  0X  denotes  hexadecimal.	  Otherwise,  numbers  take  the  form
       [base#]n,  where	the optional base is a decimal number between 2	and 64
       representing the	arithmetic base, and n is a number in that  base.   If
       base#  is omitted, then base 10 is used.	 When specifying n, the	digits
       greater than 9 are represented by the lowercase letters,	the  uppercase
       letters,	@, and _, in that order.  If base is less than or equal	to 36,
       lowercase and uppercase letters may be used interchangeably  to	repre-
       sent numbers between 10 and 35.

       Operators  are  evaluated  in  order of precedence.  Sub-expressions in
       parentheses are evaluated first and may override	the  precedence	 rules
       above.

CONDITIONAL EXPRESSIONS
       Conditional  expressions	 are  used  by the [[ compound command and the
       test and	[ builtin commands to test file	attributes and perform	string
       and  arithmetic comparisons.  Expressions are formed from the following
       unary or	binary primaries.  Bash	handles	 several  filenames  specially
       when  they  are	used in	expressions.  If the operating system on which
       bash is running provides	these special files, bash will use them;  oth-
       erwise  it will emulate them internally with this behavior: If any file
       argument	to one of the primaries	is of the form	/dev/fd/n,  then  file
       descriptor  n is	checked.  If the file argument to one of the primaries
       is one of /dev/stdin, /dev/stdout, or /dev/stderr, file	descriptor  0,
       1, or 2,	respectively, is checked.

       Unless otherwise	specified, primaries that operate on files follow sym-
       bolic links and operate on the target of	the link, rather than the link
       itself.

       When  used  with	[[, the	< and >	operators sort lexicographically using
       the current locale.  The	test command sorts using ASCII ordering.

       -a file
	      True if file exists.
       -b file
	      True if file exists and is a block special file.
       -c file
	      True if file exists and is a character special file.
       -d file
	      True if file exists and is a directory.
       -e file
	      True if file exists.
       -f file
	      True if file exists and is a regular file.
       -g file
	      True if file exists and is set-group-id.
       -h file
	      True if file exists and is a symbolic link.
       -k file
	      True if file exists and its ``sticky'' bit is set.
       -p file
	      True if file exists and is a named pipe (FIFO).
       -r file
	      True if file exists and is readable.
       -s file
	      True if file exists and has a size greater than zero.
       -t fd  True if file descriptor fd is open and refers to a terminal.
       -u file
	      True if file exists and its set-user-id bit is set.
       -w file
	      True if file exists and is writable.
       -x file
	      True if file exists and is executable.
       -G file
	      True if file exists and is owned by the effective	group id.
       -L file
	      True if file exists and is a symbolic link.
       -N file
	      True if file exists and has been	modified  since	 it  was  last
	      read.
       -O file
	      True if file exists and is owned by the effective	user id.
       -S file
	      True if file exists and is a socket.
       file1 -ef file2
	      True  if file1 and file2 refer to	the same device	and inode num-
	      bers.
       file1 -nt file2
	      True if file1 is newer (according	 to  modification  date)  than
	      file2, or	if file1 exists	and file2 does not.
       file1 -ot file2
	      True  if file1 is	older than file2, or if	file2 exists and file1
	      does not.
       -o optname
	      True if the shell	option optname is enabled.  See	 the  list  of
	      options  under  the  description	of  the	 -o  option to the set
	      builtin below.
       -v varname
	      True if the shell	variable varname is set	(has been  assigned  a
	      value).
       -R varname
	      True  if	the shell variable varname is set and is a name	refer-
	      ence.
       -z string
	      True if the length of string is zero.
       string
       -n string
	      True if the length of string is non-zero.

       string1 == string2
       string1 = string2
	      True if the strings are equal.  =	should be used with  the  test
	      command  for  POSIX conformance.	When used with the [[ command,
	      this performs pattern matching as	described above	(Compound Com-
	      mands).

       string1 != string2
	      True if the strings are not equal.

       string1 < string2
	      True if string1 sorts before string2 lexicographically.

       string1 > string2
	      True if string1 sorts after string2 lexicographically.

       arg1 OP arg2
	      OP  is one of -eq, -ne, -lt, -le,	-gt, or	-ge.  These arithmetic
	      binary operators return true if arg1 is equal to,	not equal  to,
	      less  than, less than or equal to, greater than, or greater than
	      or equal to arg2,	respectively.  Arg1 and	arg2 may  be  positive
	      or negative integers.

SIMPLE COMMAND EXPANSION
       When  a	simple	command	 is executed, the shell	performs the following
       expansions, assignments,	and redirections, from left to right.

       1.     The words	that the parser	has  marked  as	 variable  assignments
	      (those  preceding	 the  command name) and	redirections are saved
	      for later	processing.

       2.     The words	that are not variable assignments or redirections  are
	      expanded.	  If  any words	remain after expansion,	the first word
	      is taken to be the name of the command and the  remaining	 words
	      are the arguments.

       3.     Redirections are performed as described above under REDIRECTION.

       4.     The text after the = in each variable assignment undergoes tilde
	      expansion, parameter expansion, command substitution, arithmetic
	      expansion, and quote removal before being	assigned to the	 vari-
	      able.

       If no command name results, the variable	assignments affect the current
       shell environment.  Otherwise, the variables are	added to the  environ-
       ment  of	the executed command and do not	affect the current shell envi-
       ronment.	 If any	of the assignments attempts to assign  a  value	 to  a
       readonly	 variable,  an error occurs, and the command exits with	a non-
       zero status.

       If no command name results, redirections	 are  performed,  but  do  not
       affect  the  current shell environment.	A redirection error causes the
       command to exit with a non-zero status.

       If there	is a command name left after expansion,	execution proceeds  as
       described  below.   Otherwise, the command exits.  If one of the	expan-
       sions contained a command substitution, the exit	status of the  command
       is  the	exit  status  of  the last command substitution	performed.  If
       there were no command substitutions, the	command	exits with a status of
       zero.

COMMAND	EXECUTION
       After  a	 command  has been split into words, if	it results in a	simple
       command and an optional list of arguments, the  following  actions  are
       taken.

       If  the	command	name contains no slashes, the shell attempts to	locate
       it.  If there exists a shell function by	that name,  that  function  is
       invoked	as described above in FUNCTIONS.  If the name does not match a
       function, the shell searches for	it in the list of shell	builtins.   If
       a match is found, that builtin is invoked.

       If  the name is neither a shell function	nor a builtin, and contains no
       slashes,	bash searches each element of the PATH for  a  directory  con-
       taining	an  executable	file  by that name.  Bash uses a hash table to
       remember	the full pathnames of executable files (see hash  under	 SHELL
       BUILTIN	COMMANDS  below).  A full search of the	directories in PATH is
       performed only if the command is	not found in the hash table.   If  the
       search is unsuccessful, the shell searches for a	defined	shell function
       named command_not_found_handle.	If that	function exists, it is invoked
       with  the  original command and the original command's arguments	as its
       arguments, and the function's exit status becomes the  exit  status  of
       the  shell.  If that function is	not defined, the shell prints an error
       message and returns an exit status of 127.

       If the search is	successful, or if the command  name  contains  one  or
       more slashes, the shell executes	the named program in a separate	execu-
       tion environment.  Argument 0 is	set to the name	given, and the remain-
       ing arguments to	the command are	set to the arguments given, if any.

       If  this	 execution fails because the file is not in executable format,
       and the file is not a directory,	it is assumed to be a shell script,  a
       file  containing	 shell commands.  A subshell is	spawned	to execute it.
       This subshell reinitializes itself, so that the effect is as if	a  new
       shell  had  been	 invoked to handle the script, with the	exception that
       the locations of	commands remembered by	the  parent  (see  hash	 below
       under SHELL BUILTIN COMMANDS) are retained by the child.

       If  the program is a file beginning with	#!, the	remainder of the first
       line specifies an interpreter for the program.  The shell executes  the
       specified interpreter on	operating systems that do not handle this exe-
       cutable format themselves.  The arguments to the	interpreter consist of
       a  single optional argument following the interpreter name on the first
       line of the program, followed by	the name of the	program,  followed  by
       the command arguments, if any.

COMMAND	EXECUTION ENVIRONMENT
       The  shell  has an execution environment, which consists	of the follow-
       ing:

       o      open files inherited by the shell	at invocation, as modified  by
	      redirections supplied to the exec	builtin

       o      the  current  working directory as set by	cd, pushd, or popd, or
	      inherited	by the shell at	invocation

       o      the file creation	mode mask as set by umask  or  inherited  from
	      the shell's parent

       o      current traps set	by trap

       o      shell parameters that are	set by variable	assignment or with set
	      or inherited from	the shell's parent in the environment

       o      shell functions defined during execution or inherited  from  the
	      shell's parent in	the environment

       o      options  enabled	at  invocation (either by default or with com-
	      mand-line	arguments) or by set

       o      options enabled by shopt

       o      shell aliases defined with alias

       o      various process IDs, including those  of	background  jobs,  the
	      value of $$, and the value of PPID

       When  a	simple command other than a builtin or shell function is to be
       executed, it is invoked in a separate execution environment  that  con-
       sists  of the following.	 Unless	otherwise noted, the values are	inher-
       ited from the shell.

       o      the shell's open files, plus  any	 modifications	and  additions
	      specified	by redirections	to the command

       o      the current working directory

       o      the file creation	mode mask

       o      shell  variables	and  functions	marked	for export, along with
	      variables	exported for the command, passed in the	environment

       o      traps caught by the shell	are reset to the values	inherited from
	      the shell's parent, and traps ignored by the shell are ignored

       A  command  invoked  in	this  separate	environment  cannot affect the
       shell's execution environment.

       Command substitution, commands grouped with parentheses,	and  asynchro-
       nous commands are invoked in a subshell environment that	is a duplicate
       of the shell environment, except	that traps caught  by  the  shell  are
       reset to	the values that	the shell inherited from its parent at invoca-
       tion.  Builtin commands that are	invoked	as part	of a pipeline are also
       executed	in a subshell environment.  Changes made to the	subshell envi-
       ronment cannot affect the shell's execution environment.

       Subshells spawned to execute command substitutions inherit the value of
       the  -e	option	from  the  parent shell.  When not in posix mode, bash
       clears the -e option in such subshells.

       If a command is followed	by a & and job	control	 is  not  active,  the
       default	standard  input	 for  the command is the empty file /dev/null.
       Otherwise, the invoked command inherits the  file  descriptors  of  the
       calling shell as	modified by redirections.

ENVIRONMENT
       When  a	program	 is invoked it is given	an array of strings called the
       environment.   This  is	a  list	 of  name-value	 pairs,	 of  the  form
       name=value.

       The  shell  provides  several  ways  to manipulate the environment.  On
       invocation, the shell scans its own environment and creates a parameter
       for  each name found, automatically marking it for export to child pro-
       cesses.	Executed commands inherit the  environment.   The  export  and
       declare	-x  commands allow parameters and functions to be added	to and
       deleted from the	environment.  If the value of a	parameter in the envi-
       ronment	is  modified,  the  new	value becomes part of the environment,
       replacing the old.  The environment inherited by	any  executed  command
       consists	 of the	shell's	initial	environment, whose values may be modi-
       fied in the shell, less any pairs removed by the	 unset	command,  plus
       any additions via the export and	declare	-x commands.

       The  environment	 for  any  simple command or function may be augmented
       temporarily by prefixing	it with	parameter  assignments,	 as  described
       above in	PARAMETERS.  These assignment statements affect	only the envi-
       ronment seen by that command.

       If the -k option	is set (see the	set builtin command below),  then  all
       parameter  assignments are placed in the	environment for	a command, not
       just those that precede the command name.

       When bash invokes an external command, the variable _  is  set  to  the
       full filename of	the command and	passed to that command in its environ-
       ment.

EXIT STATUS
       The exit	status of an executed command is the  value  returned  by  the
       waitpid system call or equivalent function.  Exit statuses fall between
       0 and 255, though, as explained below, the shell	may use	 values	 above
       125 specially.  Exit statuses from shell	builtins and compound commands
       are also	limited	to this	range.	Under certain circumstances, the shell
       will use	special	values to indicate specific failure modes.

       For the shell's purposes, a command which exits with a zero exit	status
       has succeeded.  An exit status of zero indicates	success.   A  non-zero
       exit  status  indicates	failure.  When a command terminates on a fatal
       signal N, bash uses the value of	128+N as the exit status.

       If a command is not found, the child  process  created  to  execute  it
       returns	a status of 127.  If a command is found	but is not executable,
       the return status is 126.

       If a command fails because of an	error during expansion or redirection,
       the exit	status is greater than zero.

       Shell  builtin  commands	return a status	of 0 (true) if successful, and
       non-zero	(false)	if an error occurs while they execute.	 All  builtins
       return  an  exit	 status	 of  2	to indicate incorrect usage, generally
       invalid options or missing arguments.

       Bash itself returns the exit  status  of	 the  last  command  executed,
       unless  a  syntax  error	occurs,	in which case it exits with a non-zero
       value.  See also	the exit builtin command below.

SIGNALS
       When bash is interactive, in the	 absence  of  any  traps,  it  ignores
       SIGTERM (so that	kill 0 does not	kill an	interactive shell), and	SIGINT
       is caught and handled (so that the wait builtin is interruptible).   In
       all  cases,  bash  ignores  SIGQUIT.  If	job control is in effect, bash
       ignores SIGTTIN,	SIGTTOU, and SIGTSTP.

       Non-builtin commands run	by bash	have signal handlers set to the	values
       inherited  by  the  shell  from its parent.  When job control is	not in
       effect, asynchronous commands ignore SIGINT and SIGQUIT in addition  to
       these  inherited	handlers.  Commands run	as a result of command substi-
       tution ignore the keyboard-generated job	control	signals	SIGTTIN, SIGT-
       TOU, and	SIGTSTP.

       The  shell  exits by default upon receipt of a SIGHUP.  Before exiting,
       an interactive shell  resends  the  SIGHUP  to  all  jobs,  running  or
       stopped.	 Stopped jobs are sent SIGCONT to ensure that they receive the
       SIGHUP.	To prevent the shell from sending the signal to	 a  particular
       job,  it	 should	be removed from	the jobs table with the	disown builtin
       (see SHELL BUILTIN COMMANDS below) or  marked  to  not  receive	SIGHUP
       using disown -h.

       If  the	huponexit  shell  option has been set with shopt, bash sends a
       SIGHUP to all jobs when an interactive login shell exits.

       If bash is waiting for a	command	to complete and	receives a signal  for
       which a trap has	been set, the trap will	not be executed	until the com-
       mand completes.	When bash is waiting for an asynchronous  command  via
       the  wait  builtin, the reception of a signal for which a trap has been
       set will	cause the wait builtin to return immediately with an exit sta-
       tus greater than	128, immediately after which the trap is executed.

JOB CONTROL
       Job  control  refers  to	 the ability to	selectively stop (suspend) the
       execution of processes and continue (resume) their execution at a later
       point.	A  user	 typically  employs  this  facility via	an interactive
       interface supplied jointly by the operating  system  kernel's  terminal
       driver and bash.

       The  shell  associates  a  job with each	pipeline.  It keeps a table of
       currently executing jobs, which may be listed with  the	jobs  command.
       When  bash starts a job asynchronously (in the background), it prints a
       line that looks like:

	      [1] 25647

       indicating that this job	is job number 1	and that the process ID	of the
       last process in the pipeline associated with this job is	25647.	All of
       the processes in	a single pipeline are members of the same  job.	  Bash
       uses the	job abstraction	as the basis for job control.

       To  facilitate the implementation of the	user interface to job control,
       the operating system maintains the notion of a current terminal process
       group ID.  Members of this process group	(processes whose process group
       ID is equal to the current terminal process group ID) receive keyboard-
       generated  signals  such	 as SIGINT.  These processes are said to be in
       the foreground.	Background processes are those whose process group  ID
       differs from the	terminal's; such processes are immune to keyboard-gen-
       erated signals.	Only foreground	processes are allowed to read from or,
       if  the	user  so  specifies  with  stty	tostop,	write to the terminal.
       Background processes which attempt to read from	(write	to  when  stty
       tostop  is  in effect) the terminal are sent a SIGTTIN (SIGTTOU)	signal
       by the kernel's terminal	driver,	which,	unless	caught,	 suspends  the
       process.

       If  the operating system	on which bash is running supports job control,
       bash contains facilities	to use it.  Typing the suspend character (typ-
       ically ^Z, Control-Z) while a process is	running	causes that process to
       be stopped and returns control to bash.	 Typing	 the  delayed  suspend
       character  (typically  ^Y,  Control-Y) causes the process to be stopped
       when it attempts	to read	input from the terminal,  and  control	to  be
       returned	 to bash.  The user may	then manipulate	the state of this job,
       using the bg command to continue	it in the background, the  fg  command
       to continue it in the foreground, or the	kill command to	kill it.  A ^Z
       takes effect immediately, and has the additional	side effect of causing
       pending output and typeahead to be discarded.

       There are a number of ways to refer to a	job in the shell.  The charac-
       ter % introduces	a job specification (jobspec).	Job number  n  may  be
       referred	to as %n.  A job may also be referred to using a prefix	of the
       name used to start it, or using a substring that	appears	in its command
       line.   For  example,  %ce  refers  to  a  stopped ce job.  If a	prefix
       matches more than one job, bash reports an error.  Using	%?ce,  on  the
       other  hand,  refers to any job containing the string ce	in its command
       line.  If the substring matches more than  one  job,  bash  reports  an
       error.	The  symbols %%	and %+ refer to	the shell's notion of the cur-
       rent job, which is the last job stopped while it	was in the  foreground
       or started in the background.  The previous job may be referenced using
       %-.  If there is	only a single job, %+ and %- can both be used to refer
       to  that	 job.	In  output pertaining to jobs (e.g., the output	of the
       jobs command), the current job is always	flagged	with a +, and the pre-
       vious  job  with	 a -.  A single	% (with	no accompanying	job specifica-
       tion) also refers to the	current	job.

       Simply naming a job can be used to bring	it into	the foreground:	%1  is
       a  synonym  for	``fg %1'', bringing job	1 from the background into the
       foreground.  Similarly, ``%1 &''	 resumes  job  1  in  the  background,
       equivalent to ``bg %1''.

       The  shell  learns immediately whenever a job changes state.  Normally,
       bash waits until	it is about to print a prompt before reporting changes
       in  a  job's status so as to not	interrupt any other output.  If	the -b
       option to the set builtin command is enabled, bash reports such changes
       immediately.   Any  trap	 on  SIGCHLD  is  executed for each child that
       exits.

       If an attempt to	exit bash is made while	jobs are stopped (or,  if  the
       checkjobs  shell	 option	has been enabled using the shopt builtin, run-
       ning), the shell	prints a warning message, and, if the checkjobs	option
       is  enabled,  lists  the	jobs and their statuses.  The jobs command may
       then be used to inspect their status.  If a second attempt to  exit  is
       made  without  an intervening command, the shell	does not print another
       warning,	and any	stopped	jobs are terminated.

PROMPTING
       When executing interactively, bash displays the primary prompt PS1 when
       it  is  ready  to  read a command, and the secondary prompt PS2 when it
       needs more input	to complete a command.	Bash  displays	PS0  after  it
       reads  a	 command  but  before  executing it.  Bash allows these	prompt
       strings to be customized	by inserting  a	 number	 of  backslash-escaped
       special characters that are decoded as follows:
	      \a     an	ASCII bell character (07)
	      \d     the  date	in "Weekday Month Date"	format (e.g., "Tue May
		     26")
	      \D{format}
		     the format	is passed to strftime(3)  and  the  result  is
		     inserted  into the	prompt string; an empty	format results
		     in	a locale-specific time representation.	The braces are
		     required
	      \e     an	ASCII escape character (033)
	      \h     the hostname up to	the first `.'
	      \H     the hostname
	      \j     the number	of jobs	currently managed by the shell
	      \l     the basename of the shell's terminal device name
	      \n     newline
	      \r     carriage return
	      \s     the  name	of  the	shell, the basename of $0 (the portion
		     following the final slash)
	      \t     the current time in 24-hour HH:MM:SS format
	      \T     the current time in 12-hour HH:MM:SS format
	      \@     the current time in 12-hour am/pm format
	      \A     the current time in 24-hour HH:MM format
	      \u     the username of the current user
	      \v     the version of bash (e.g.,	2.00)
	      \V     the release of bash, version + patch level	(e.g., 2.00.0)
	      \w     the  current  working  directory,	with $HOME abbreviated
		     with a tilde (uses	the value of the PROMPT_DIRTRIM	 vari-
		     able)
	      \W     the basename of the current working directory, with $HOME
		     abbreviated with a	tilde
	      \!     the history number	of this	command
	      \#     the command number	of this	command
	      \$     if	the effective UID is 0,	a #, otherwise a $
	      \nnn   the character corresponding to the	octal number nnn
	      \\     a backslash
	      \[     begin a sequence of non-printing characters, which	 could
		     be	 used  to  embed  a terminal control sequence into the
		     prompt
	      \]     end a sequence of non-printing characters

       The command number and the history number are  usually  different:  the
       history	number of a command is its position in the history list, which
       may include commands  restored  from  the  history  file	 (see  HISTORY
       below),	while  the  command  number is the position in the sequence of
       commands	executed during	the current shell session.  After  the	string
       is  decoded,  it	is expanded via	parameter expansion, command substitu-
       tion, arithmetic	expansion, and quote removal, subject to the value  of
       the  promptvars	shell option (see the description of the shopt command
       under SHELL BUILTIN COMMANDS below).

READLINE
       This is the library that	handles	reading	input when using  an  interac-
       tive shell, unless the --noediting option is given at shell invocation.
       Line editing is also used when using the	-e option to the read builtin.
       By default, the line editing commands are similar to those of Emacs.  A
       vi-style	line editing interface is also available.  Line	editing	can be
       enabled	at  any	 time  using  the -o emacs or -o vi options to the set
       builtin (see SHELL BUILTIN COMMANDS below).  To turn off	 line  editing
       after  the  shell  is running, use the +o emacs or +o vi	options	to the
       set builtin.

   Readline Notation
       In this section,	the Emacs-style	notation is used to denote keystrokes.
       Control	keys  are  denoted by C-key, e.g., C-n means Control-N.	 Simi-
       larly, meta keys	are denoted by M-key, so M-x means Meta-X.   (On  key-
       boards  without a meta key, M-x means ESC x, i.e., press	the Escape key
       then the	x key.	This makes ESC the meta	prefix.	 The combination M-C-x
       means  ESC-Control-x, or	press the Escape key then hold the Control key
       while pressing the x key.)

       Readline	commands may be	given numeric arguments, which normally	act as
       a  repeat  count.   Sometimes,  however,	it is the sign of the argument
       that is significant.  Passing a negative	argument  to  a	 command  that
       acts  in	the forward direction (e.g., kill-line)	causes that command to
       act in a	backward direction.  Commands whose  behavior  with  arguments
       deviates	from this are noted below.

       When  a command is described as killing text, the text deleted is saved
       for possible future retrieval (yanking).	 The killed text is saved in a
       kill ring.  Consecutive kills cause the text to be accumulated into one
       unit, which can be yanked all at	once.  Commands	which do not kill text
       separate	the chunks of text on the kill ring.

   Readline Initialization
       Readline	 is  customized	 by putting commands in	an initialization file
       (the inputrc file).  The	name of	this file is taken from	the  value  of
       the  INPUTRC  variable.	 If  that  variable  is	 unset,	the default is
       ~/.inputrc.  When a program which uses the readline library starts  up,
       the initialization file is read,	and the	key bindings and variables are
       set.  There are only a few basic	constructs  allowed  in	 the  readline
       initialization  file.  Blank lines are ignored.	Lines beginning	with a
       # are comments.	Lines beginning	with a	$  indicate  conditional  con-
       structs.	 Other lines denote key	bindings and variable settings.

       The  default  key-bindings  may be changed with an inputrc file.	 Other
       programs	that use this library may add their own	commands and bindings.

       For example, placing

	      M-Control-u: universal-argument
       or
	      C-Meta-u:	universal-argument
       into  the inputrc would make M-C-u execute the readline command univer-
       sal-argument.

       The following symbolic character	names  are  recognized:	 RUBOUT,  DEL,
       ESC, LFD, NEWLINE, RET, RETURN, SPC, SPACE, and TAB.

       In  addition  to	 command  names, readline allows keys to be bound to a
       string that is inserted when the	key is pressed (a macro).

   Readline Key	Bindings
       The syntax for controlling key bindings in the inputrc file is  simple.
       All  that is required is	the name of the	command	or the text of a macro
       and a key sequence to which it should be	bound.	The name may be	speci-
       fied in one of two ways:	as a symbolic key name,	possibly with Meta- or
       Control-	prefixes, or as	a key sequence.

       When using the form keyname:function-name or macro, keyname is the name
       of a key	spelled	out in English.	 For example:

	      Control-u: universal-argument
	      Meta-Rubout: backward-kill-word
	      Control-o: "> output"

       In  the above example, C-u is bound to the function universal-argument,
       M-DEL is	bound to the function backward-kill-word, and C-o is bound  to
       run  the	macro expressed	on the right hand side (that is, to insert the
       text ``>	output'' into the line).

       In the second form, "keyseq":function-name  or  macro,  keyseq  differs
       from  keyname above in that strings denoting an entire key sequence may
       be specified by placing the sequence within double  quotes.   Some  GNU
       Emacs  style  key escapes can be	used, as in the	following example, but
       the symbolic character names are	not recognized.

	      "\C-u": universal-argument
	      "\C-x\C-r": re-read-init-file
	      "\e[11~":	"Function Key 1"

       In this example,	C-u is again bound to the function universal-argument.
       C-x  C-r	is bound to the	function re-read-init-file, and	ESC [ 1	1 ~ is
       bound to	insert the text	``Function Key 1''.

       The full	set of GNU Emacs style escape sequences	is
	      \C-    control prefix
	      \M-    meta prefix
	      \e     an	escape character
	      \\     backslash
	      \"     literal "
	      \'     literal '

       In addition to the GNU Emacs style escape sequences, a  second  set  of
       backslash escapes is available:
	      \a     alert (bell)
	      \b     backspace
	      \d     delete
	      \f     form feed
	      \n     newline
	      \r     carriage return
	      \t     horizontal	tab
	      \v     vertical tab
	      \nnn   the  eight-bit  character	whose value is the octal value
		     nnn (one to three digits)
	      \xHH   the eight-bit character whose value  is  the  hexadecimal
		     value HH (one or two hex digits)

       When entering the text of a macro, single or double quotes must be used
       to indicate a macro definition.	Unquoted text is assumed to be a func-
       tion  name.   In	 the macro body, the backslash escapes described above
       are expanded.  Backslash	will quote any other character	in  the	 macro
       text, including " and '.

       Bash  allows the	current	readline key bindings to be displayed or modi-
       fied with the bind builtin command.  The	editing	mode may  be  switched
       during  interactive  use	by using the -o	option to the set builtin com-
       mand (see SHELL BUILTIN COMMANDS	below).

   Readline Variables
       Readline	has variables that can be used to further customize its	behav-
       ior.  A variable	may be set in the inputrc file with a statement	of the
       form

	      set variable-name	value

       Except where noted, readline variables can take the values  On  or  Off
       (without	 regard	 to  case).   Unrecognized variable names are ignored.
       When a variable value is	read, empty or null values, "on"  (case-insen-
       sitive),	and "1"	are equivalent to On.  All other values	are equivalent
       to Off.	The variables and their	default	values are:

       bell-style (audible)
	      Controls what happens when readline wants	to ring	 the  terminal
	      bell.  If	set to none, readline never rings the bell.  If	set to
	      visible, readline	uses a visible bell if one is  available.   If
	      set to audible, readline attempts	to ring	the terminal's bell.
       bind-tty-special-chars (On)
	      If  set  to On, readline attempts	to bind	the control characters
	      treated specially	by the kernel's	terminal driver	to their read-
	      line equivalents.
       blink-matching-paren (Off)
	      If set to	On, readline attempts to briefly move the cursor to an
	      opening parenthesis when a closing parenthesis is	inserted.
       colored-completion-prefix (Off)
	      If set to	On, when listing completions,  readline	 displays  the
	      common prefix of the set of possible completions using a differ-
	      ent color.  The color definitions	are taken from	the  value  of
	      the LS_COLORS environment	variable.
       colored-stats (Off)
	      If  set to On, readline displays possible	completions using dif-
	      ferent colors to indicate	their file type.   The	color  defini-
	      tions  are  taken	 from  the  value of the LS_COLORS environment
	      variable.
       comment-begin (``#'')
	      The string that is inserted  when	 the  readline	insert-comment
	      command is executed.  This command is bound to M-# in emacs mode
	      and to # in vi command mode.
       completion-display-width	(-1)
	      The number of screen columns used	to  display  possible  matches
	      when  performing completion.  The	value is ignored if it is less
	      than 0 or	greater	than the terminal screen width.	 A value of  0
	      will  cause  matches  to be displayed one	per line.  The default
	      value is -1.
       completion-ignore-case (Off)
	      If set to	On, readline performs filename matching	and completion
	      in a case-insensitive fashion.
       completion-map-case (Off)
	      If  set  to  On, and completion-ignore-case is enabled, readline
	      treats hyphens (-) and underscores (_) as	equivalent  when  per-
	      forming case-insensitive filename	matching and completion.
       completion-prefix-display-length	(0)
	      The  length in characters	of the common prefix of	a list of pos-
	      sible completions	that is	displayed without modification.	  When
	      set  to  a  value	greater	than zero, common prefixes longer than
	      this value are replaced with an ellipsis when displaying	possi-
	      ble completions.
       completion-query-items (100)
	      This  determines when the	user is	queried	about viewing the num-
	      ber of possible completions generated  by	 the  possible-comple-
	      tions  command.  It may be set to	any integer value greater than
	      or equal to zero.	 If the	 number	 of  possible  completions  is
	      greater than or equal to the value of this variable, the user is
	      asked whether or not he wishes to	view them; otherwise they  are
	      simply listed on the terminal.
       convert-meta (On)
	      If  set  to On, readline will convert characters with the	eighth
	      bit set to an ASCII key sequence by stripping the	eighth bit and
	      prefixing	 an  escape  character (in effect, using escape	as the
	      meta prefix).  The default is On,	but readline will  set	it  to
	      Off if the locale	contains eight-bit characters.
       disable-completion (Off)
	      If set to	On, readline will inhibit word completion.  Completion
	      characters will be inserted into the line	as if  they  had  been
	      mapped to	self-insert.
       echo-control-characters (On)
	      When  set	to On, on operating systems that indicate they support
	      it, readline echoes a character corresponding to a signal	gener-
	      ated from	the keyboard.
       editing-mode (emacs)
	      Controls whether readline	begins with a set of key bindings sim-
	      ilar to Emacs or vi.  editing-mode can be	set to either emacs or
	      vi.
       enable-bracketed-paste (Off)
	      When  set	 to  On, readline will configure the terminal in a way
	      that will	enable it to insert each paste into the	editing	buffer
	      as a single string of characters,	instead	of treating each char-
	      acter as if it had been read from	the keyboard.  This  can  pre-
	      vent  pasted  characters	from being interpreted as editing com-
	      mands.
       enable-keypad (Off)
	      When set to On, readline will try	to enable the application key-
	      pad  when	 it  is	 called.  Some systems need this to enable the
	      arrow keys.
       enable-meta-key (On)
	      When set to On, readline will try	to enable  any	meta  modifier
	      key  the	terminal claims	to support when	it is called.  On many
	      terminals, the meta key is used to send eight-bit	characters.
       expand-tilde (Off)
	      If set  to  On,  tilde  expansion	 is  performed	when  readline
	      attempts word completion.
       history-preserve-point (Off)
	      If  set  to  On, the history code	attempts to place point	at the
	      same location on each history line retrieved with	 previous-his-
	      tory or next-history.
       history-size (unset)
	      Set  the	maximum	number of history entries saved	in the history
	      list.  If	set to zero, any existing history entries are  deleted
	      and no new entries are saved.  If	set to a value less than zero,
	      the number of history entries is not limited.  By	 default,  the
	      number  of  history  entries is set to the value of the HISTSIZE
	      shell variable.  If an attempt is	made to	set history-size to  a
	      non-numeric value, the maximum number of history entries will be
	      set to 500.
       horizontal-scroll-mode (Off)
	      When set to On, makes readline use a single  line	 for  display,
	      scrolling	the input horizontally on a single screen line when it
	      becomes longer than the screen width rather than wrapping	 to  a
	      new line.
       input-meta (Off)
	      If  set to On, readline will enable eight-bit input (that	is, it
	      will not strip the eighth	bit from  the  characters  it  reads),
	      regardless of what the terminal claims it	can support.  The name
	      meta-flag	is a synonym for this variable.	 The default  is  Off,
	      but  readline will set it	to On if the locale contains eight-bit
	      characters.
       isearch-terminators (``C-[C-J'')
	      The string of characters that should  terminate  an  incremental
	      search  without  subsequently  executing the character as	a com-
	      mand.  If	this variable has not been given a value, the  charac-
	      ters ESC and C-J will terminate an incremental search.
       keymap (emacs)
	      Set  the current readline	keymap.	 The set of valid keymap names
	      is emacs,	emacs-standard,	emacs-meta,  emacs-ctlx,  vi,  vi-com-
	      mand,  and  vi-insert.  vi is equivalent to vi-command; emacs is
	      equivalent to emacs-standard.  The default value is  emacs;  the
	      value of editing-mode also affects the default keymap.
       emacs-mode-string (@)
	      This string is displayed immediately before the last line	of the
	      primary prompt when emacs	editing	mode is	active.	 The value  is
	      expanded	like  a	 key binding, so the standard set of meta- and
	      control prefixes and backslash escape  sequences	is  available.
	      Use  the	\1  and	 \2 escapes to begin and end sequences of non-
	      printing characters, which can be	used to	embed a	terminal  con-
	      trol sequence into the mode string.
       keyseq-timeout (500)
	      Specifies	 the  duration readline	will wait for a	character when
	      reading an ambiguous key sequence	(one that can form a  complete
	      key sequence using the input read	so far,	or can take additional
	      input to complete	a  longer  key	sequence).   If	 no  input  is
	      received	within	the timeout, readline will use the shorter but
	      complete key sequence.  The value	is specified in	 milliseconds,
	      so  a value of 1000 means	that readline will wait	one second for
	      additional input.	 If this variable is set to a value less  than
	      or  equal	to zero, or to a non-numeric value, readline will wait
	      until another key	is pressed to decide  which  key  sequence  to
	      complete.
       mark-directories	(On)
	      If set to	On, completed directory	names have a slash appended.
       mark-modified-lines (Off)
	      If  set  to  On,	history	lines that have	been modified are dis-
	      played with a preceding asterisk (*).
       mark-symlinked-directories (Off)
	      If set to	On, completed names which are symbolic links to	direc-
	      tories   have   a	 slash	appended  (subject  to	the  value  of
	      mark-directories).
       match-hidden-files (On)
	      This variable, when set to On, causes readline  to  match	 files
	      whose  names  begin  with	 a  `.'	(hidden	files) when performing
	      filename completion.  If set to Off, the	leading	 `.'  must  be
	      supplied by the user in the filename to be completed.
       menu-complete-display-prefix (Off)
	      If  set to On, menu completion displays the common prefix	of the
	      list of possible completions (which may be empty)	before cycling
	      through the list.
       output-meta (Off)
	      If  set  to On, readline will display characters with the	eighth
	      bit set directly rather than as a	meta-prefixed escape sequence.
	      The default is Off, but readline will set	it to On if the	locale
	      contains eight-bit characters.
       page-completions	(On)
	      If set to	On, readline uses an internal more-like	pager to  dis-
	      play a screenful of possible completions at a time.
       print-completions-horizontally (Off)
	      If  set  to  On,	readline will display completions with matches
	      sorted horizontally in alphabetical order, rather	than down  the
	      screen.
       revert-all-at-newline (Off)
	      If  set  to  On, readline	will undo all changes to history lines
	      before returning when accept-line	is executed.  By default, his-
	      tory  lines  may	be  modified  and retain individual undo lists
	      across calls to readline.
       show-all-if-ambiguous (Off)
	      This alters the default behavior of  the	completion  functions.
	      If set to	On, words which	have more than one possible completion
	      cause the	matches	to be listed immediately  instead  of  ringing
	      the bell.
       show-all-if-unmodified (Off)
	      This  alters the default behavior	of the completion functions in
	      a	fashion	similar	to show-all-if-ambiguous.  If set to On, words
	      which  have more than one	possible completion without any	possi-
	      ble partial completion (the possible completions don't  share  a
	      common  prefix)  cause  the  matches  to	be  listed immediately
	      instead of ringing the bell.
       show-mode-in-prompt (Off)
	      If set to	On, add	a character to the  beginning  of  the	prompt
	      indicating  the  editing	mode:  emacs (@), vi command (:) or vi
	      insertion	(+).
       skip-completed-text (Off)
	      If set to	On, this alters	the default completion	behavior  when
	      inserting	 a  single match into the line.	 It's only active when
	      performing completion in the middle  of  a  word.	  If  enabled,
	      readline	does  not  insert  characters from the completion that
	      match characters after point in the  word	 being	completed,  so
	      portions of the word following the cursor	are not	duplicated.
       vi-cmd-mode-string ((cmd))
	      This string is displayed immediately before the last line	of the
	      primary prompt when vi editing mode is  active  and  in  command
	      mode.  The value is expanded like	a key binding, so the standard
	      set of meta- and control prefixes	and backslash escape sequences
	      is  available.   Use  the	 \1  and  \2  escapes to begin and end
	      sequences	of non-printing	characters, which can be used to embed
	      a	terminal control sequence into the mode	string.
       vi-ins-mode-string ((ins))
	      This string is displayed immediately before the last line	of the
	      primary prompt when vi editing mode is active and	 in  insertion
	      mode.  The value is expanded like	a key binding, so the standard
	      set of meta- and control prefixes	and backslash escape sequences
	      is  available.   Use  the	 \1  and  \2  escapes to begin and end
	      sequences	of non-printing	characters, which can be used to embed
	      a	terminal control sequence into the mode	string.
       visible-stats (Off)
	      If  set to On, a character denoting a file's type	as reported by
	      stat(2) is appended to the filename when listing	possible  com-
	      pletions.

   Readline Conditional	Constructs
       Readline	 implements  a	facility  similar in spirit to the conditional
       compilation features of the C preprocessor which	 allows	 key  bindings
       and  variable  settings	to be performed	as the result of tests.	 There
       are four	parser directives used.

       $if    The $if construct	allows bindings	to be made based on the	 edit-
	      ing  mode,  the  terminal	 being	used, or the application using
	      readline.	 The text of the test extends to the end of the	 line;
	      no characters are	required to isolate it.

	      mode   The  mode=	 form  of  the	$if  directive is used to test
		     whether readline is in emacs or vi	 mode.	 This  may  be
		     used  in  conjunction  with  the  set keymap command, for
		     instance, to  set	bindings  in  the  emacs-standard  and
		     emacs-ctlx	 keymaps  only	if readline is starting	out in
		     emacs mode.

	      term   The term= form may	be used	to  include  terminal-specific
		     key bindings, perhaps to bind the key sequences output by
		     the terminal's function keys.  The	word on	the right side
		     of	the = is tested	against	both the full name of the ter-
		     minal and the portion of the  terminal  name  before  the
		     first  -.	This allows sun	to match both sun and sun-cmd,
		     for instance.

	      application
		     The application construct is used to include application-
		     specific  settings.   Each	 program  using	 the  readline
		     library sets the application name,	and an	initialization
		     file can test for a particular value.  This could be used
		     to	bind key sequences to functions	useful for a  specific
		     program.	For instance, the following command adds a key
		     sequence that quotes the  current	or  previous  word  in
		     bash:

		     $if Bash
		     # Quote the current or previous word
		     "\C-xq": "\eb\"\ef\""
		     $endif

       $endif This command, as seen in the previous example, terminates	an $if
	      command.

       $else  Commands in this branch of the $if directive are executed	if the
	      test fails.

       $include
	      This  directive takes a single filename as an argument and reads
	      commands and bindings from that file.  For example, the  follow-
	      ing directive would read /etc/inputrc:

	      $include	/etc/inputrc

   Searching
       Readline	 provides  commands  for searching through the command history
       (see HISTORY below) for lines containing	a specified string.  There are
       two search modes: incremental and non-incremental.

       Incremental  searches  begin  before  the  user has finished typing the
       search string.  As each character of the	search string is typed,	 read-
       line displays the next entry from the history matching the string typed
       so far.	An incremental search requires	only  as  many	characters  as
       needed  to  find	 the desired history entry.  The characters present in
       the value of the	isearch-terminators variable are used to terminate  an
       incremental search.  If that variable has not been assigned a value the
       Escape and Control-J characters will terminate an  incremental  search.
       Control-G  will	abort  an  incremental search and restore the original
       line.  When the search is terminated, the history entry containing  the
       search string becomes the current line.

       To  find	 other matching	entries	in the history list, type Control-S or
       Control-R as appropriate.  This will search backward or forward in  the
       history	for  the  next	entry matching the search string typed so far.
       Any other key sequence bound to a readline command will	terminate  the
       search  and  execute that command.  For instance, a newline will	termi-
       nate the	search and accept the line, thereby executing the command from
       the history list.

       Readline	remembers the last incremental search string.  If two Control-
       Rs are typed without any	intervening characters defining	a  new	search
       string, any remembered search string is used.

       Non-incremental	searches read the entire search	string before starting
       to search for matching history lines.  The search string	may  be	 typed
       by the user or be part of the contents of the current line.

   Readline Command Names
       The  following  is  a list of the names of the commands and the default
       key sequences to	which they are bound.  Command names without an	accom-
       panying key sequence are	unbound	by default.  In	the following descrip-
       tions, point refers to the current cursor position, and mark refers  to
       a  cursor position saved	by the set-mark	command.  The text between the
       point and mark is referred to as	the region.

   Commands for	Moving
       beginning-of-line (C-a)
	      Move to the start	of the current line.
       end-of-line (C-e)
	      Move to the end of the line.
       forward-char (C-f)
	      Move forward a character.
       backward-char (C-b)
	      Move back	a character.
       forward-word (M-f)
	      Move forward to the end of the next word.	 Words are composed of
	      alphanumeric characters (letters and digits).
       backward-word (M-b)
	      Move  back  to the start of the current or previous word.	 Words
	      are composed of alphanumeric characters (letters and digits).
       shell-forward-word
	      Move forward to the end of the next word.	 Words	are  delimited
	      by non-quoted shell metacharacters.
       shell-backward-word
	      Move  back  to the start of the current or previous word.	 Words
	      are delimited by non-quoted shell	metacharacters.
       clear-screen (C-l)
	      Clear the	screen leaving the current line	 at  the  top  of  the
	      screen.	With  an  argument,  refresh  the current line without
	      clearing the screen.
       redraw-current-line
	      Refresh the current line.

   Commands for	Manipulating the History
       accept-line (Newline, Return)
	      Accept the line regardless of where the cursor is.  If this line
	      is  non-empty, add it to the history list	according to the state
	      of the HISTCONTROL variable.  If the line	is a modified  history
	      line, then restore the history line to its original state.
       previous-history	(C-p)
	      Fetch the	previous command from the history list,	moving back in
	      the list.
       next-history (C-n)
	      Fetch the	next command from the history list, moving forward  in
	      the list.
       beginning-of-history (M-<)
	      Move to the first	line in	the history.
       end-of-history (M->)
	      Move  to	the end	of the input history, i.e., the	line currently
	      being entered.
       reverse-search-history (C-r)
	      Search backward starting at the current  line  and  moving  `up'
	      through  the  history  as	 necessary.   This  is	an incremental
	      search.
       forward-search-history (C-s)
	      Search forward starting at the current line  and	moving	`down'
	      through  the  history  as	 necessary.   This  is	an incremental
	      search.
       non-incremental-reverse-search-history (M-p)
	      Search backward through the history starting at the current line
	      using  a	non-incremental	 search	 for  a	string supplied	by the
	      user.
       non-incremental-forward-search-history (M-n)
	      Search forward  through  the  history  using  a  non-incremental
	      search for a string supplied by the user.
       history-search-forward
	      Search  forward through the history for the string of characters
	      between the start	of the current line and	the point.  This is  a
	      non-incremental search.
       history-search-backward
	      Search backward through the history for the string of characters
	      between the start	of the current line and	the point.  This is  a
	      non-incremental search.
       yank-nth-arg (M-C-y)
	      Insert  the  first argument to the previous command (usually the
	      second word on the previous line)	at point.  With	an argument n,
	      insert  the nth word from	the previous command (the words	in the
	      previous command	begin  with  word  0).	 A  negative  argument
	      inserts the nth word from	the end	of the previous	command.  Once
	      the argument n is	computed, the argument is extracted as if  the
	      "!n" history expansion had been specified.
       yank-last-arg (M-., M-_)
	      Insert  the last argument	to the previous	command	(the last word
	      of the previous history entry).  With a numeric argument,	behave
	      exactly  like  yank-nth-arg.   Successive	calls to yank-last-arg
	      move back	through	the history list, inserting the	last word  (or
	      the  word	 specified  by the argument to the first call) of each
	      line in turn.  Any numeric argument supplied to these successive
	      calls  determines	 the direction to move through the history.  A
	      negative argument	switches the  direction	 through  the  history
	      (back or forward).  The history expansion	facilities are used to
	      extract the last word, as	if the "!$" history expansion had been
	      specified.
       shell-expand-line (M-C-e)
	      Expand the line as the shell does.  This performs	alias and his-
	      tory expansion as	well as	all of the shell word expansions.  See
	      HISTORY  EXPANSION below for a description of history expansion.
       history-expand-line (M-^)
	      Perform history expansion	on  the	 current  line.	  See  HISTORY
	      EXPANSION	below for a description	of history expansion.
       magic-space
	      Perform  history	expansion  on  the  current  line and insert a
	      space.  See HISTORY EXPANSION below for a	description of history
	      expansion.
       alias-expand-line
	      Perform  alias expansion on the current line.  See ALIASES above
	      for a description	of alias expansion.
       history-and-alias-expand-line
	      Perform history and alias	expansion on the current line.
       insert-last-argument (M-., M-_)
	      A	synonym	for yank-last-arg.
       operate-and-get-next (C-o)
	      Accept the current line for execution and	fetch  the  next  line
	      relative	to the current line from the history for editing.  Any
	      argument is ignored.
       edit-and-execute-command	(C-xC-e)
	      Invoke an	editor on the current command line,  and  execute  the
	      result  as  shell	 commands.   Bash  attempts to invoke $VISUAL,
	      $EDITOR, and emacs as the	editor,	in that	order.

   Commands for	Changing Text
       end-of-file (usually C-d)
	      The character indicating end-of-file as  set,  for  example,  by
	      ``stty''.	  If  this character is	read when there	are no charac-
	      ters on the line,	and point is at	the  beginning	of  the	 line,
	      Readline interprets it as	the end	of input and returns EOF.
       delete-char (C-d)
	      Delete the character at point.  If this function is bound	to the
	      same character as	the tty	EOF character, as C-d commonly is, see
	      above for	the effects.
       backward-delete-char (Rubout)
	      Delete  the  character  behind the cursor.  When given a numeric
	      argument,	save the deleted text on the kill ring.
       forward-backward-delete-char
	      Delete the character under the cursor, unless the	cursor	is  at
	      the end of the line, in which case the character behind the cur-
	      sor is deleted.
       quoted-insert (C-q, C-v)
	      Add the next character typed to the line verbatim.  This is  how
	      to insert	characters like	C-q, for example.
       tab-insert (C-v TAB)
	      Insert a tab character.
       self-insert (a, b, A, 1,	!, ...)
	      Insert the character typed.
       transpose-chars (C-t)
	      Drag  the	 character  before point forward over the character at
	      point, moving point forward as well.  If point is	at the end  of
	      the  line, then this transposes the two characters before	point.
	      Negative arguments have no effect.
       transpose-words (M-t)
	      Drag the word before point past the  word	 after	point,	moving
	      point  over  that	 word  as well.	 If point is at	the end	of the
	      line, this transposes the	last two words on the line.
       upcase-word (M-u)
	      Uppercase	the current (or	 following)  word.   With  a  negative
	      argument,	uppercase the previous word, but do not	move point.
       downcase-word (M-l)
	      Lowercase	 the  current  (or  following)	word.  With a negative
	      argument,	lowercase the previous word, but do not	move point.
       capitalize-word (M-c)
	      Capitalize the current (or following)  word.   With  a  negative
	      argument,	capitalize the previous	word, but do not move point.
       overwrite-mode
	      Toggle  overwrite	mode.  With an explicit	positive numeric argu-
	      ment, switches to	overwrite mode.	 With an explicit non-positive
	      numeric argument,	switches to insert mode.  This command affects
	      only emacs mode; vi mode does overwrite differently.  Each  call
	      to readline() starts in insert mode.  In overwrite mode, charac-
	      ters bound to self-insert	replace	the text at point rather  than
	      pushing  the  text  to  the  right.   Characters	bound to back-
	      ward-delete-char replace	the  character	before	point  with  a
	      space.  By default, this command is unbound.

   Killing and Yanking
       kill-line (C-k)
	      Kill the text from point to the end of the line.
       backward-kill-line (C-x Rubout)
	      Kill backward to the beginning of	the line.
       unix-line-discard (C-u)
	      Kill  backward  from  point  to  the beginning of	the line.  The
	      killed text is saved on the kill-ring.
       kill-whole-line
	      Kill all characters on the current line, no matter  where	 point
	      is.
       kill-word (M-d)
	      Kill  from  point	 to the	end of the current word, or if between
	      words, to	the end	of the next word.   Word  boundaries  are  the
	      same as those used by forward-word.
       backward-kill-word (M-Rubout)
	      Kill  the	 word  behind  point.  Word boundaries are the same as
	      those used by backward-word.
       shell-kill-word
	      Kill from	point to the end of the	current	word,  or  if  between
	      words,  to  the  end  of the next	word.  Word boundaries are the
	      same as those used by shell-forward-word.
       shell-backward-kill-word
	      Kill the word behind point.  Word	boundaries  are	 the  same  as
	      those used by shell-backward-word.
       unix-word-rubout	(C-w)
	      Kill  the	 word behind point, using white	space as a word	bound-
	      ary.  The	killed text is saved on	the kill-ring.
       unix-filename-rubout
	      Kill the word behind point, using	 white	space  and  the	 slash
	      character	 as  the word boundaries.  The killed text is saved on
	      the kill-ring.
       delete-horizontal-space (M-\)
	      Delete all spaces	and tabs around	point.
       kill-region
	      Kill the text in the current region.
       copy-region-as-kill
	      Copy the text in the region to the kill buffer.
       copy-backward-word
	      Copy the word before point to the	kill buffer.  The word	bound-
	      aries are	the same as backward-word.
       copy-forward-word
	      Copy  the	 word  following  point	 to the	kill buffer.  The word
	      boundaries are the same as forward-word.
       yank (C-y)
	      Yank the top of the kill ring into the buffer at point.
       yank-pop	(M-y)
	      Rotate the kill ring, and	yank the new top.  Only	works  follow-
	      ing yank or yank-pop.

   Numeric Arguments
       digit-argument (M-0, M-1, ..., M--)
	      Add  this	digit to the argument already accumulating, or start a
	      new argument.  M-- starts	a negative argument.
       universal-argument
	      This is another way to specify an	argument.  If this command  is
	      followed	by one or more digits, optionally with a leading minus
	      sign, those digits define	the argument.  If the command is  fol-
	      lowed  by	 digits,  executing  universal-argument	again ends the
	      numeric argument,	but is otherwise ignored.  As a	special	 case,
	      if  this	command	is immediately followed	by a character that is
	      neither a	digit nor minus	sign, the argument count for the  next
	      command  is multiplied by	four.  The argument count is initially
	      one, so executing	this function the first	time makes  the	 argu-
	      ment count four, a second	time makes the argument	count sixteen,
	      and so on.

   Completing
       complete	(TAB)
	      Attempt to perform completion on the text	 before	 point.	  Bash
	      attempts completion treating the text as a variable (if the text
	      begins with $), username (if the text begins with	 ~),  hostname
	      (if  the	text begins with @), or	command	(including aliases and
	      functions) in turn.  If none of these produces a match, filename
	      completion is attempted.
       possible-completions (M-?)
	      List the possible	completions of the text	before point.
       insert-completions (M-*)
	      Insert  all completions of the text before point that would have
	      been generated by	possible-completions.
       menu-complete
	      Similar to complete, but replaces	the word to be completed  with
	      a	 single	match from the list of possible	completions.  Repeated
	      execution	of menu-complete steps through the  list  of  possible
	      completions,  inserting  each  match in turn.  At	the end	of the
	      list of completions, the bell is rung (subject to	the setting of
	      bell-style) and the original text	is restored.  An argument of n
	      moves n positions	forward	in the list  of	 matches;  a  negative
	      argument	may  be	 used to move backward through the list.  This
	      command is intended to be	 bound	to  TAB,  but  is  unbound  by
	      default.
       menu-complete-backward
	      Identical	 to menu-complete, but moves backward through the list
	      of possible completions, as if menu-complete had	been  given  a
	      negative argument.  This command is unbound by default.
       delete-char-or-list
	      Deletes  the  character under the	cursor if not at the beginning
	      or end of	the line (like delete-char).  If at  the  end  of  the
	      line, behaves identically	to possible-completions.  This command
	      is unbound by default.
       complete-filename (M-/)
	      Attempt filename completion on the text before point.
       possible-filename-completions (C-x /)
	      List the possible	completions of the text	before point, treating
	      it as a filename.
       complete-username (M-~)
	      Attempt  completion  on  the text	before point, treating it as a
	      username.
       possible-username-completions (C-x ~)
	      List the possible	completions of the text	before point, treating
	      it as a username.
       complete-variable (M-$)
	      Attempt  completion  on  the text	before point, treating it as a
	      shell variable.
       possible-variable-completions (C-x $)
	      List the possible	completions of the text	before point, treating
	      it as a shell variable.
       complete-hostname (M-@)
	      Attempt  completion  on  the text	before point, treating it as a
	      hostname.
       possible-hostname-completions (C-x @)
	      List the possible	completions of the text	before point, treating
	      it as a hostname.
       complete-command	(M-!)
	      Attempt  completion  on  the text	before point, treating it as a
	      command name.  Command completion	attempts  to  match  the  text
	      against	aliases,   reserved   words,  shell  functions,	 shell
	      builtins,	and finally executable filenames, in that order.
       possible-command-completions (C-x !)
	      List the possible	completions of the text	before point, treating
	      it as a command name.
       dynamic-complete-history	(M-TAB)
	      Attempt  completion on the text before point, comparing the text
	      against lines from the  history  list  for  possible  completion
	      matches.
       dabbrev-expand
	      Attempt  menu completion on the text before point, comparing the
	      text against lines from the history list for possible completion
	      matches.
       complete-into-braces (M-{)
	      Perform filename completion and insert the list of possible com-
	      pletions enclosed	within braces so the list is available to  the
	      shell (see Brace Expansion above).

   Keyboard Macros
       start-kbd-macro (C-x ()
	      Begin  saving  the  characters  typed  into the current keyboard
	      macro.
       end-kbd-macro (C-x ))
	      Stop saving the characters typed into the	current	keyboard macro
	      and store	the definition.
       call-last-kbd-macro (C-x	e)
	      Re-execute  the last keyboard macro defined, by making the char-
	      acters in	the macro appear as if typed at	the keyboard.
       print-last-kbd-macro ()
	      Print the	last keyboard macro defined in a format	 suitable  for
	      the inputrc file.

   Miscellaneous
       re-read-init-file (C-x C-r)
	      Read  in	the  contents of the inputrc file, and incorporate any
	      bindings or variable assignments found there.
       abort (C-g)
	      Abort the	current	editing	command	and ring the  terminal's  bell
	      (subject to the setting of bell-style).
       do-uppercase-version (M-a, M-b, M-x, ...)
	      If  the  metafied	character x is lowercase, run the command that
	      is bound to the corresponding uppercase character.
       prefix-meta (ESC)
	      Metafy the next character	typed.	ESC f is equivalent to Meta-f.
       undo (C-_, C-x C-u)
	      Incremental undo,	separately remembered for each line.
       revert-line (M-r)
	      Undo  all	changes	made to	this line.  This is like executing the
	      undo command enough times	to return  the	line  to  its  initial
	      state.
       tilde-expand (M-&)
	      Perform tilde expansion on the current word.
       set-mark	(C-@, M-<space>)
	      Set  the	mark to	the point.  If a numeric argument is supplied,
	      the mark is set to that position.
       exchange-point-and-mark (C-x C-x)
	      Swap the point with the mark.  The current  cursor  position  is
	      set  to the saved	position, and the old cursor position is saved
	      as the mark.
       character-search	(C-])
	      A	character is read and point is moved to	the next occurrence of
	      that  character.	 A negative count searches for previous	occur-
	      rences.
       character-search-backward (M-C-])
	      A	character is read and point is moved to	 the  previous	occur-
	      rence  of	 that character.  A negative count searches for	subse-
	      quent occurrences.
       skip-csi-sequence
	      Read enough characters to	consume	a multi-key sequence  such  as
	      those  defined for keys like Home	and End.  Such sequences begin
	      with a Control Sequence Indicator	(CSI), usually ESC-[.  If this
	      sequence	is  bound  to "\[", keys producing such	sequences will
	      have no effect unless explicitly bound to	 a  readline  command,
	      instead  of  inserting stray characters into the editing buffer.
	      This is unbound by default, but usually bound to ESC-[.
       insert-comment (M-#)
	      Without a	numeric	argument,  the	value  of  the	readline  com-
	      ment-begin  variable is inserted at the beginning	of the current
	      line.  If	a numeric argument is supplied,	this command acts as a
	      toggle:  if  the	characters at the beginning of the line	do not
	      match the	value of comment-begin,	the value is inserted,	other-
	      wise the characters in comment-begin are deleted from the	begin-
	      ning of the line.	 In either case, the line is accepted as if  a
	      newline  had  been  typed.   The	default	value of comment-begin
	      causes this command to make the current line  a  shell  comment.
	      If  a  numeric  argument	causes	the  comment  character	 to be
	      removed, the line	will be	executed by the	shell.
       glob-complete-word (M-g)
	      The word before point is	treated	 as  a	pattern	 for  pathname
	      expansion,  with	an asterisk implicitly appended.  This pattern
	      is used to generate a list of matching  filenames	 for  possible
	      completions.
       glob-expand-word	(C-x *)
	      The  word	 before	 point	is  treated  as	a pattern for pathname
	      expansion, and the  list	of  matching  filenames	 is  inserted,
	      replacing	 the  word.   If  a  numeric  argument is supplied, an
	      asterisk is appended before pathname expansion.
       glob-list-expansions (C-x g)
	      The list	of  expansions	that  would  have  been	 generated  by
	      glob-expand-word	is  displayed,	and the	line is	redrawn.  If a
	      numeric argument is supplied, an	asterisk  is  appended	before
	      pathname expansion.
       dump-functions
	      Print  all  of the functions and their key bindings to the read-
	      line output stream.  If a	numeric	argument is supplied, the out-
	      put  is  formatted  in such a way	that it	can be made part of an
	      inputrc file.
       dump-variables
	      Print all	of the settable	readline variables and their values to
	      the  readline output stream.  If a numeric argument is supplied,
	      the output is formatted in such a	way that it can	be  made  part
	      of an inputrc file.
       dump-macros
	      Print  all of the	readline key sequences bound to	macros and the
	      strings they output.  If a numeric  argument  is	supplied,  the
	      output is	formatted in such a way	that it	can be made part of an
	      inputrc file.
       display-shell-version (C-x C-v)
	      Display version information about	the current instance of	 bash.

   Programmable	Completion
       When  word  completion  is  attempted  for an argument to a command for
       which a completion specification	(a compspec) has  been	defined	 using
       the  complete  builtin  (see  SHELL  BUILTIN  COMMANDS below), the pro-
       grammable completion facilities are invoked.

       First, the command name is identified.  If  the	command	 word  is  the
       empty  string (completion attempted at the beginning of an empty	line),
       any compspec defined with the -E	option to  complete  is	 used.	 If  a
       compspec	 has  been  defined  for that command, the compspec is used to
       generate	the list of possible completions for the word.	If the command
       word  is	 a full	pathname, a compspec for the full pathname is searched
       for first.  If no compspec is found for the full	pathname,  an  attempt
       is  made	 to find a compspec for	the portion following the final	slash.
       If those	searches do not	result in a  compspec,	any  compspec  defined
       with the	-D option to complete is used as the default.

       Once  a	compspec  has  been  found, it is used to generate the list of
       matching	words.	If a compspec is not found, the	default	 bash  comple-
       tion as described above under Completing	is performed.

       First,  the  actions  specified by the compspec are used.  Only matches
       which are prefixed by the word being completed are returned.  When  the
       -f  or -d option	is used	for filename or	directory name completion, the
       shell variable FIGNORE is used to filter	the matches.

       Any completions specified by a pathname expansion  pattern  to  the  -G
       option are generated next.  The words generated by the pattern need not
       match the word being completed.	The GLOBIGNORE shell variable  is  not
       used to filter the matches, but the FIGNORE variable is used.

       Next,  the string specified as the argument to the -W option is consid-
       ered.  The string is first split	using the characters in	the  IFS  spe-
       cial  variable  as delimiters.  Shell quoting is	honored.  Each word is
       then expanded using brace expansion,  tilde  expansion,	parameter  and
       variable	 expansion, command substitution, and arithmetic expansion, as
       described above under EXPANSION.	 The results are split using the rules
       described above under Word Splitting.  The results of the expansion are
       prefix-matched against the word being completed,	and the	matching words
       become the possible completions.

       After  these matches have been generated, any shell function or command
       specified with the -F and -C options is invoked.	 When the  command  or
       function	is invoked, the	COMP_LINE, COMP_POINT, COMP_KEY, and COMP_TYPE
       variables are assigned values as	described above	under Shell Variables.
       If  a  shell  function  is being	invoked, the COMP_WORDS	and COMP_CWORD
       variables are also set.	When the function or command is	 invoked,  the
       first  argument	($1)  is  the  name of the command whose arguments are
       being completed,	the second argument ($2) is the	word being  completed,
       and  the	 third argument	($3) is	the word preceding the word being com-
       pleted on the current command line.  No filtering of the	generated com-
       pletions	against	the word being completed is performed; the function or
       command has complete freedom in generating the matches.

       Any function specified with -F is invoked first.	 The function may  use
       any  of	the  shell facilities, including the compgen builtin described
       below, to generate the matches.	It must	put the	 possible  completions
       in the COMPREPLY	array variable,	one per	array element.

       Next,  any  command specified with the -C option	is invoked in an envi-
       ronment equivalent to command substitution.  It should print a list  of
       completions,  one  per  line, to	the standard output.  Backslash	may be
       used to escape a	newline, if necessary.

       After all of the	possible completions are generated, any	filter	speci-
       fied  with  the -X option is applied to the list.  The filter is	a pat-
       tern as used for	pathname expansion; a &	in  the	 pattern  is  replaced
       with  the text of the word being	completed.  A literal &	may be escaped
       with a backslash; the backslash is removed before attempting  a	match.
       Any  completion that matches the	pattern	will be	removed	from the list.
       A leading ! negates the pattern;	in this	case any completion not	match-
       ing  the	 pattern  will be removed.  If the nocasematch shell option is
       enabled,	the match is performed without regard to the  case  of	alpha-
       betic characters.

       Finally,	any prefix and suffix specified	with the -P and	-S options are
       added to	each member of the completion list, and	the result is returned
       to the readline completion code as the list of possible completions.

       If  the previously-applied actions do not generate any matches, and the
       -o dirnames option was supplied	to  complete  when  the	 compspec  was
       defined,	directory name completion is attempted.

       If  the	-o  plusdirs option was	supplied to complete when the compspec
       was defined, directory name completion is attempted and any matches are
       added to	the results of the other actions.

       By  default,  if	a compspec is found, whatever it generates is returned
       to the completion code as the full set of  possible  completions.   The
       default bash completions	are not	attempted, and the readline default of
       filename	completion is disabled.	 If the	-o bashdefault option was sup-
       plied  to complete when the compspec was	defined, the bash default com-
       pletions	are attempted if the compspec generates	no matches.  If	the -o
       default	option was supplied to complete	when the compspec was defined,
       readline's default completion will be performed if the  compspec	 (and,
       if attempted, the default bash completions) generate no matches.

       When  a	compspec  indicates that directory name	completion is desired,
       the programmable	completion functions force readline to append a	 slash
       to  completed names which are symbolic links to directories, subject to
       the value of the	mark-directories readline variable, regardless of  the
       setting of the mark-symlinked-directories readline variable.

       There  is  some support for dynamically modifying completions.  This is
       most useful when	used in	combination with a default  completion	speci-
       fied  with  complete -D.	 It's possible for shell functions executed as
       completion handlers to indicate that completion should  be  retried  by
       returning  an exit status of 124.  If a shell function returns 124, and
       changes the compspec associated with the	command	on which completion is
       being  attempted	 (supplied  as the first argument when the function is
       executed), programmable completion restarts from	the beginning, with an
       attempt	to find	a new compspec for that	command.  This allows a	set of
       completions to be built dynamically as completion is attempted,	rather
       than being loaded all at	once.

       For  instance, assuming that there is a library of compspecs, each kept
       in a file corresponding to the  name  of	 the  command,	the  following
       default completion function would load completions dynamically:

       _completion_loader()
       {
	    . "/etc/bash_completion.d/$1.sh" >/dev/null	2>&1 &&	return 124
       }
       complete	-D -F _completion_loader -o bashdefault	-o default

HISTORY
       When  the  -o  history  option to the set builtin is enabled, the shell
       provides	access to the command history, the list	of commands previously
       typed.	The  value  of	the HISTSIZE variable is used as the number of
       commands	to save	in a history list.  The	text of	the last HISTSIZE com-
       mands  (default	500)  is  saved.  The shell stores each	command	in the
       history list prior to parameter and variable expansion  (see  EXPANSION
       above)  but after history expansion is performed, subject to the	values
       of the shell variables HISTIGNORE and HISTCONTROL.

       On startup, the history is initialized from the file named by the vari-
       able  HISTFILE  (default	~/.bash_history).  The file named by the value
       of HISTFILE is truncated, if necessary, to contain  no  more  than  the
       number  of  lines specified by the value	of HISTFILESIZE.  If HISTFILE-
       SIZE is unset, or set to	null, a	non-numeric value, or a	numeric	 value
       less  than  zero,  the history file is not truncated.  When the history
       file is read, lines beginning with the history comment  character  fol-
       lowed immediately by a digit are	interpreted as timestamps for the pre-
       ceding history line.  These timestamps are optionally displayed depend-
       ing  on	the  value  of the HISTTIMEFORMAT variable.  When a shell with
       history enabled exits, the last $HISTSIZE lines	are  copied  from  the
       history	list  to $HISTFILE.  If	the histappend shell option is enabled
       (see the	description of shopt under SHELL BUILTIN COMMANDS below),  the
       lines  are  appended to the history file, otherwise the history file is
       overwritten.   If  HISTFILE  is	unset,	or  if	the  history  file  is
       unwritable,  the	 history is not	saved.	If the HISTTIMEFORMAT variable
       is set, time stamps are written to the history file,  marked  with  the
       history	comment	 character, so they may	be preserved across shell ses-
       sions.  This uses the history comment character	to  distinguish	 time-
       stamps from other history lines.	 After saving the history, the history
       file is truncated to contain no more than HISTFILESIZE lines.  If HIST-
       FILESIZE	 is  unset,  or	set to null, a non-numeric value, or a numeric
       value less than zero, the history file is not truncated.

       The builtin command fc (see SHELL BUILTIN COMMANDS below) may  be  used
       to list or edit and re-execute a	portion	of the history list.  The his-
       tory builtin may	be used	to display or  modify  the  history  list  and
       manipulate  the	history	file.  When using command-line editing,	search
       commands	are available in each editing mode that	provide	access to  the
       history list.

       The  shell  allows control over which commands are saved	on the history
       list.  The HISTCONTROL and HISTIGNORE variables may be set to cause the
       shell to	save only a subset of the commands entered.  The cmdhist shell
       option, if enabled, causes the shell to attempt to save each line of  a
       multi-line  command  in the same	history	entry, adding semicolons where
       necessary to preserve syntactic correctness.  The lithist shell	option
       causes  the shell to save the command with embedded newlines instead of
       semicolons.  See	the description	of the shopt builtin below under SHELL
       BUILTIN	COMMANDS  for  information  on	setting	 and  unsetting	 shell
       options.

HISTORY	EXPANSION
       The shell supports a history expansion feature that is similar  to  the
       history	expansion in csh.  This	section	describes what syntax features
       are available.  This feature is	enabled	 by  default  for  interactive
       shells, and can be disabled using the +H	option to the set builtin com-
       mand (see SHELL BUILTIN COMMANDS	below).	 Non-interactive shells	do not
       perform history expansion by default.

       History expansions introduce words from the history list	into the input
       stream, making it easy to repeat	commands, insert the  arguments	 to  a
       previous	command	into the current input line, or	fix errors in previous
       commands	quickly.

       History expansion is performed immediately after	 a  complete  line  is
       read,  before  the  shell  breaks it into words.	 It takes place	in two
       parts.  The first is to determine which line from the history  list  to
       use during substitution.	 The second is to select portions of that line
       for inclusion into the current one.  The	line selected from the history
       is  the	event,	and  the portions of that line that are	acted upon are
       words.  Various modifiers are  available	 to  manipulate	 the  selected
       words.  The line	is broken into words in	the same fashion as when read-
       ing input, so that several metacharacter-separated words	surrounded  by
       quotes  are  considered one word.  History expansions are introduced by
       the appearance of the  history  expansion  character,  which  is	 !  by
       default.	  Only	backslash  (\) and single quotes can quote the history
       expansion character,  but  the  history	expansion  character  is  also
       treated	as  quoted if it immediately precedes the closing double quote
       in a double-quoted string.

       Several characters inhibit history expansion if found immediately  fol-
       lowing  the history expansion character,	even if	it is unquoted:	space,
       tab, newline, carriage return, and =.  If the extglob shell  option  is
       enabled,	( will also inhibit expansion.

       Several	shell  options	settable with the shopt	builtin	may be used to
       tailor the behavior of history  expansion.   If	the  histverify	 shell
       option is enabled (see the description of the shopt builtin below), and
       readline	is being  used,	 history  substitutions	 are  not  immediately
       passed  to  the	shell  parser.	Instead, the expanded line is reloaded
       into the	readline editing buffer	for further modification.  If readline
       is  being  used,	 and  the histreedit shell option is enabled, a	failed
       history substitution will be reloaded into the readline editing	buffer
       for  correction.	  The  -p option to the	history	builtin	command	may be
       used to see what	a history expansion will do before using it.   The  -s
       option to the history builtin may be used to add	commands to the	end of
       the history list	without	actually executing  them,  so  that  they  are
       available for subsequent	recall.

       The  shell allows control of the	various	characters used	by the history
       expansion mechanism (see	the description	of histchars above under Shell
       Variables).   The shell uses the	history	comment	character to mark his-
       tory timestamps when writing the	history	file.

   Event Designators
       An event	designator is a	reference to a command line entry in the  his-
       tory  list.   Unless  the reference is absolute,	events are relative to
       the current position in the history list.

       !      Start a history substitution, except when	followed by  a	blank,
	      newline,	carriage return, = or (	(when the extglob shell	option
	      is enabled using the shopt builtin).
       !n     Refer to command line n.
       !-n    Refer to the current command minus n.
       !!     Refer to the previous command.  This is a	synonym	for `!-1'.
       !string
	      Refer to the most	recent command preceding the current  position
	      in the history list starting with	string.
       !?string[?]
	      Refer  to	the most recent	command	preceding the current position
	      in the history list containing string.  The trailing  ?  may  be
	      omitted if string	is followed immediately	by a newline.
       ^string1^string2^
	      Quick  substitution.   Repeat  the  previous  command, replacing
	      string1 with string2.  Equivalent	 to  ``!!:s/string1/string2/''
	      (see Modifiers below).
       !#     The entire command line typed so far.

   Word	Designators
       Word  designators are used to select desired words from the event.  A :
       separates the event specification from the word designator.  It may  be
       omitted	if  the	word designator	begins with a ^, $, *, -, or %.	 Words
       are numbered from the beginning of the line, with the first word	 being
       denoted	by  0  (zero).	Words are inserted into	the current line sepa-
       rated by	single spaces.

       0 (zero)
	      The zeroth word.	For the	shell, this is the command word.
       n      The nth word.
       ^      The first	argument.  That	is, word 1.
       $      The last word.  This is usually  the  last  argument,  but  will
	      expand to	the zeroth word	if there is only one word in the line.
       %      The word matched by the most recent `?string?' search.
       x-y    A	range of words;	`-y' abbreviates `0-y'.
       *      All of the words but the zeroth.	This is	a synonym  for	`1-$'.
	      It  is  not  an  error to	use * if there is just one word	in the
	      event; the empty string is returned in that case.
       x*     Abbreviates x-$.
       x-     Abbreviates x-$ like x*, but omits the last word.

       If a word designator is supplied	without	an  event  specification,  the
       previous	command	is used	as the event.

   Modifiers
       After  the optional word	designator, there may appear a sequence	of one
       or more of the following	modifiers, each	preceded by a `:'.

       h      Remove a trailing	filename component, leaving only the head.
       t      Remove all leading filename components, leaving the tail.
       r      Remove a trailing	suffix of the form .xxx, leaving the basename.
       e      Remove all but the trailing suffix.
       p      Print the	new command but	do not execute it.
       q      Quote the	substituted words, escaping further substitutions.
       x      Quote  the  substituted words as with q, but break into words at
	      blanks and newlines.
       s/old/new/
	      Substitute new for the first occurrence  of  old	in  the	 event
	      line.   Any  delimiter  can  be  used  in	place of /.  The final
	      delimiter	is optional if it is the last character	of  the	 event
	      line.   The delimiter may	be quoted in old and new with a	single
	      backslash.  If & appears in new, it is replaced by old.  A  sin-
	      gle  backslash  will  quote the &.  If old is null, it is	set to
	      the last old substituted,	or, if no previous  history  substitu-
	      tions took place,	the last string	in a !?string[?]  search.
       &      Repeat the previous substitution.
       g      Cause changes to be applied over the entire event	line.  This is
	      used in conjunction with `:s' (e.g.,  `:gs/old/new/')  or	 `:&'.
	      If  used with `:s', any delimiter	can be used in place of	/, and
	      the final	delimiter is optional if it is the last	 character  of
	      the event	line.  An a may	be used	as a synonym for g.
       G      Apply  the following `s' modifier	once to	each word in the event
	      line.

SHELL BUILTIN COMMANDS
       Unless otherwise	noted, each builtin command documented in this section
       as accepting options preceded by	- accepts -- to	signify	the end	of the
       options.	 The :,	true, false, and test builtins do not  accept  options
       and  do	not treat -- specially.	 The exit, logout, return, break, con-
       tinue, let, and shift builtins accept and process  arguments  beginning
       with  - without requiring --.  Other builtins that accept arguments but
       are not specified as accepting options  interpret  arguments  beginning
       with  -	as  invalid options and	require	-- to prevent this interpreta-
       tion.
       : [arguments]
	      No effect; the command does nothing beyond  expanding  arguments
	      and performing any specified redirections.  The return status is
	      zero.

	.  filename [arguments]
       source filename [arguments]
	      Read and execute commands	from filename  in  the	current	 shell
	      environment  and return the exit status of the last command exe-
	      cuted from filename.  If filename	 does  not  contain  a	slash,
	      filenames	 in  PATH  are	used  to find the directory containing
	      filename.	 The file searched for in PATH need not	be executable.
	      When  bash  is  not  in  posix  mode,  the  current directory is
	      searched if no file is found in PATH.  If	the sourcepath	option
	      to  the  shopt  builtin  command	is turned off, the PATH	is not
	      searched.	 If any	arguments are supplied,	they become the	 posi-
	      tional  parameters  when	filename  is  executed.	 Otherwise the
	      positional parameters  are  unchanged.   If  the	-T  option  is
	      enabled,	source	inherits  any trap on DEBUG; if	it is not, any
	      DEBUG trap string	is saved  and  restored	 around	 the  call  to
	      source,  and source unsets the DEBUG trap	while it executes.  If
	      -T is not	set, and the sourced file changes the DEBUG trap,  the
	      new  value is retained when source completes.  The return	status
	      is the status of the last	command	exited within the script (0 if
	      no commands are executed), and false if filename is not found or
	      cannot be	read.

       alias [-p] [name[=value]	...]
	      Alias with no arguments or with the -p option prints the list of
	      aliases  in  the form alias name=value on	standard output.  When
	      arguments	are supplied, an alias is defined for each name	 whose
	      value  is	given.	A trailing space in value causes the next word
	      to be checked for	alias substitution when	the alias is expanded.
	      For  each	 name  in the argument list for	which no value is sup-
	      plied, the name and  value  of  the  alias  is  printed.	 Alias
	      returns  true unless a name is given for which no	alias has been
	      defined.

       bg [jobspec ...]
	      Resume each suspended job	jobspec	in the background,  as	if  it
	      had been started with &.	If jobspec is not present, the shell's
	      notion of	the current job	is used.  bg jobspec returns 0	unless
	      run  when	 job control is	disabled or, when run with job control
	      enabled, any specified jobspec was  not  found  or  was  started
	      without job control.

       bind [-m	keymap]	[-lpsvPSVX]
       bind [-m	keymap]	[-q function] [-u function] [-r	keyseq]
       bind [-m	keymap]	-f filename
       bind [-m	keymap]	-x keyseq:shell-command
       bind [-m	keymap]	keyseq:function-name
       bind [-m	keymap]	keyseq:readline-command
	      Display  current	readline key and function bindings, bind a key
	      sequence to a readline function or  macro,  or  set  a  readline
	      variable.	  Each	non-option  argument  is a command as it would
	      appear in	.inputrc, but each binding or command must  be	passed
	      as  a  separate argument;	e.g., '"\C-x\C-r": re-read-init-file'.
	      Options, if supplied, have the following meanings:
	      -m keymap
		     Use keymap	as the keymap to be affected by	the subsequent
		     bindings.	Acceptable keymap names	are emacs, emacs-stan-
		     dard, emacs-meta, emacs-ctlx,  vi,	 vi-move,  vi-command,
		     and  vi-insert.   vi is equivalent	to vi-command (vi-move
		     is	also a synonym); emacs is  equivalent  to  emacs-stan-
		     dard.
	      -l     List the names of all readline functions.
	      -p     Display  readline	function  names	and bindings in	such a
		     way that they can be re-read.
	      -P     List current readline function names and bindings.
	      -s     Display readline key sequences bound to  macros  and  the
		     strings  they  output  in such a way that they can	be re-
		     read.
	      -S     Display readline key sequences bound to  macros  and  the
		     strings they output.
	      -v     Display  readline variable	names and values in such a way
		     that they can be re-read.
	      -V     List current readline variable names and values.
	      -f filename
		     Read key bindings from filename.
	      -q function
		     Query about which keys invoke the named function.
	      -u function
		     Unbind all	keys bound to the named	function.
	      -r keyseq
		     Remove any	current	binding	for keyseq.
	      -x keyseq:shell-command
		     Cause shell-command to be	executed  whenever  keyseq  is
		     entered.	When shell-command is executed,	the shell sets
		     the READLINE_LINE variable	to the contents	of  the	 read-
		     line  line	 buffer	and the	READLINE_POINT variable	to the
		     current location of the insertion point.  If the executed
		     command  changes  the  value  of  READLINE_LINE  or READ-
		     LINE_POINT, those new values will	be  reflected  in  the
		     editing state.
	      -X     List  all	key  sequences bound to	shell commands and the
		     associated	commands in a format that  can	be  reused  as
		     input.

	      The  return value	is 0 unless an unrecognized option is given or
	      an error occurred.

       break [n]
	      Exit from	within a for, while, until, or select loop.  If	 n  is
	      specified,  break	 n  levels.   n	must be	>= 1.  If n is greater
	      than the number of enclosing  loops,  all	 enclosing  loops  are
	      exited.	The  return value is 0 unless n	is not greater than or
	      equal to 1.

       builtin shell-builtin [arguments]
	      Execute the specified shell builtin, passing it  arguments,  and
	      return its exit status.  This is useful when defining a function
	      whose name is the	same as	a shell	builtin, retaining  the	 func-
	      tionality	of the builtin within the function.  The cd builtin is
	      commonly redefined this way.  The	 return	 status	 is  false  if
	      shell-builtin is not a shell builtin command.

       caller [expr]
	      Returns the context of any active	subroutine call	(a shell func-
	      tion or a	script executed	with the . or source builtins).	 With-
	      out expr,	caller displays	the line number	and source filename of
	      the current subroutine call.  If a non-negative integer is  sup-
	      plied as expr, caller displays the line number, subroutine name,
	      and source file corresponding to that position  in  the  current
	      execution	 call  stack.  This extra information may be used, for
	      example, to print	a stack	trace.	The current frame is frame  0.
	      The  return  value is 0 unless the shell is not executing	a sub-
	      routine call or expr does	not correspond to a valid position  in
	      the call stack.

       cd [-L|[-P [-e]]	[-@]] [dir]
	      Change  the  current  directory to dir.  if dir is not supplied,
	      the value	of the HOME shell variable is the default.  Any	 addi-
	      tional arguments following dir are ignored.  The variable	CDPATH
	      defines the search path for the directory	containing  dir:  each
	      directory	 name  in  CDPATH  is  searched	 for dir.  Alternative
	      directory	names in CDPATH	are separated by a colon (:).  A  null
	      directory	 name  in CDPATH is the	same as	the current directory,
	      i.e., ``.''.  If dir begins with a slash (/), then CDPATH	is not
	      used.   The  -P  option  causes cd to use	the physical directory
	      structure	by resolving symbolic links while traversing  dir  and
	      before processing	instances of ..	in dir (see also the -P	option
	      to the set builtin command); the -L option forces	symbolic links
	      to  be followed by resolving the link after processing instances
	      of .. in dir.  If	.. appears in dir, it is processed by removing
	      the  immediately previous	pathname component from	dir, back to a
	      slash or the beginning of	dir.  If the  -e  option  is  supplied
	      with  -P,	 and  the current working directory cannot be success-
	      fully determined after a successful directory  change,  cd  will
	      return  an unsuccessful status.  On systems that support it, the
	      -@ option	presents the extended  attributes  associated  with  a
	      file  as	a directory.  An argument of - is converted to $OLDPWD
	      before the directory change is attempted.	 If a non-empty	direc-
	      tory  name  from	CDPATH is used,	or if -	is the first argument,
	      and the directory	change is successful, the absolute pathname of
	      the  new	working	 directory  is written to the standard output.
	      The return value is  true	 if  the  directory  was  successfully
	      changed; false otherwise.

       command [-pVv] command [arg ...]
	      Run  command  with  args	suppressing  the normal	shell function
	      lookup.  Only builtin commands or	commands found in the PATH are
	      executed.	  If the -p option is given, the search	for command is
	      performed	using a	default	value for PATH that is	guaranteed  to
	      find  all	 of  the  standard  utilities.	If either the -V or -v
	      option is	supplied, a description	of command is printed.	The -v
	      option  causes  a	single word indicating the command or filename
	      used to invoke command to	be displayed; the -V option produces a
	      more  verbose  description.  If the -V or	-v option is supplied,
	      the exit status is 0 if command was found, and  1	 if  not.   If
	      neither option is	supplied and an	error occurred or command can-
	      not be found, the	exit status is 127.  Otherwise,	the exit  sta-
	      tus of the command builtin is the	exit status of command.

       compgen [option]	[word]
	      Generate	possible  completion matches for word according	to the
	      options, which may  be  any  option  accepted  by	 the  complete
	      builtin  with  the exception of -p and -r, and write the matches
	      to the standard output.  When using the -F or  -C	 options,  the
	      various  shell  variables	 set  by  the  programmable completion
	      facilities, while	available, will	not have useful	values.

	      The matches will be generated in the same	way  as	 if  the  pro-
	      grammable	 completion  code  had	generated them directly	from a
	      completion specification with the	same flags.  If	word is	speci-
	      fied, only those completions matching word will be displayed.

	      The  return  value is true unless	an invalid option is supplied,
	      or no matches were generated.

       complete	[-abcdefgjksuv]	[-o comp-option] [-DE] [-A action]  [-G	 glob-
       pat] [-W	wordlist] [-F function]	[-C command]
	      [-X filterpat] [-P prefix] [-S suffix] name [name	...]
       complete	-pr [-DE] [name	...]
	      Specify how arguments to each name should	be completed.  If  the
	      -p  option  is supplied, or if no	options	are supplied, existing
	      completion specifications	are printed in a way that allows  them
	      to be reused as input.  The -r option removes a completion spec-
	      ification	for each name, or, if no names are supplied, all  com-
	      pletion  specifications.	 The  -D  option  indicates  that  the
	      remaining	options	and actions should apply  to  the  ``default''
	      command  completion;  that is, completion	attempted on a command
	      for which	no completion has previously  been  defined.   The  -E
	      option  indicates	 that the remaining options and	actions	should
	      apply to	``empty''  command  completion;	 that  is,  completion
	      attempted	on a blank line.

	      The  process  of	applying  these	completion specifications when
	      word completion is  attempted  is	 described  above  under  Pro-
	      grammable	Completion.

	      Other  options,  if specified, have the following	meanings.  The
	      arguments	to the -G, -W, and -X options (and, if necessary,  the
	      -P  and -S options) should be quoted to protect them from	expan-
	      sion before the complete builtin is invoked.
	      -o comp-option
		      The comp-option controls several aspects	of  the	 comp-
		      spec's  behavior beyond the simple generation of comple-
		      tions.  comp-option may be one of:
		      bashdefault
			      Perform the rest of the default bash completions
			      if the compspec generates	no matches.
		      default Use  readline's  default	filename completion if
			      the compspec generates no	matches.
		      dirnames
			      Perform directory	name completion	if  the	 comp-
			      spec generates no	matches.
		      filenames
			      Tell  readline that the compspec generates file-
			      names, so	it can perform	any  filename-specific
			      processing  (like	 adding	 a  slash to directory
			      names, quoting special characters, or  suppress-
			      ing  trailing spaces).  Intended to be used with
			      shell functions.
		      noquote Tell readline not	to quote the  completed	 words
			      if  they are filenames (quoting filenames	is the
			      default).
		      nosort  Tell readline not	to sort	the list  of  possible
			      completions alphabetically.
		      nospace Tell   readline  not  to	append	a  space  (the
			      default) to words	completed at the  end  of  the
			      line.
		      plusdirs
			      After  any  matches  defined by the compspec are
			      generated,   directory   name   completion    is
			      attempted	 and  any  matches  are	 added	to the
			      results of the other actions.
	      -A action
		      The action may be	one of the  following  to  generate  a
		      list of possible completions:
		      alias   Alias names.  May	also be	specified as -a.
		      arrayvar
			      Array variable names.
		      binding Readline key binding names.
		      builtin Names  of	 shell	builtin	commands.  May also be
			      specified	as -b.
		      command Command names.  May also be specified as -c.
		      directory
			      Directory	names.	May also be specified as -d.
		      disabled
			      Names of disabled	shell builtins.
		      enabled Names of enabled shell builtins.
		      export  Names of exported	shell variables.  May also  be
			      specified	as -e.
		      file    File names.  May also be specified as -f.
		      function
			      Names of shell functions.
		      group   Group names.  May	also be	specified as -g.
		      helptopic
			      Help topics as accepted by the help builtin.
		      hostname
			      Hostnames,  as  taken from the file specified by
			      the HOSTFILE shell variable.
		      job     Job names, if job	control	is active.   May  also
			      be specified as -j.
		      keyword Shell  reserved words.  May also be specified as
			      -k.
		      running Names of running jobs, if	job control is active.
		      service Service names.  May also be specified as -s.
		      setopt  Valid  arguments	for  the  -o option to the set
			      builtin.
		      shopt   Shell option names  as  accepted	by  the	 shopt
			      builtin.
		      signal  Signal names.
		      stopped Names of stopped jobs, if	job control is active.
		      user    User names.  May also be specified as -u.
		      variable
			      Names of all shell variables.  May also be spec-
			      ified as -v.
	      -C command
		      command  is  executed in a subshell environment, and its
		      output is	used as	the possible completions.
	      -F function
		      The shell	function function is executed in  the  current
		      shell  environment.   When the function is executed, the
		      first argument ($1) is the name  of  the	command	 whose
		      arguments	 are being completed, the second argument ($2)
		      is the word being	completed, and the third argument ($3)
		      is  the  word  preceding the word	being completed	on the
		      current command line.  When it  finishes,	 the  possible
		      completions  are retrieved from the value	of the COMPRE-
		      PLY array	variable.
	      -G globpat
		      The pathname expansion pattern globpat  is  expanded  to
		      generate the possible completions.
	      -P prefix
		      prefix  is  added	at the beginning of each possible com-
		      pletion after all	other options have been	applied.
	      -S suffix
		      suffix is	appended to each possible completion after all
		      other options have been applied.
	      -W wordlist
		      The  wordlist  is	 split using the characters in the IFS
		      special variable as delimiters, and each resultant  word
		      is  expanded.   The possible completions are the members
		      of the resultant list which match	the  word  being  com-
		      pleted.
	      -X filterpat
		      filterpat	 is  a pattern as used for pathname expansion.
		      It is applied to the list	of possible completions	gener-
		      ated  by	the  preceding options and arguments, and each
		      completion matching filterpat is removed from the	 list.
		      A	 leading  !  in	filterpat negates the pattern; in this
		      case, any	completion not matching	filterpat is  removed.

	      The  return  value is true unless	an invalid option is supplied,
	      an option	other than -p or -r is supplied	without	a  name	 argu-
	      ment,  an	 attempt  is made to remove a completion specification
	      for a name for which no specification exists, or an error	occurs
	      adding a completion specification.

       compopt [-o option] [-DE] [+o option] [name]
	      Modify  completion  options  for	each  name  according  to  the
	      options, or for the currently-executing completion if  no	 names
	      are  supplied.   If no options are given,	display	the completion
	      options for each name or the current completion.	 The  possible
	      values  of  option  are  those  valid  for  the complete builtin
	      described	above.	The -D option  indicates  that	the  remaining
	      options should apply to the ``default'' command completion; that
	      is, completion attempted on a command for	 which	no  completion
	      has  previously  been defined.  The -E option indicates that the
	      remaining	options	should apply to	``empty'' command  completion;
	      that is, completion attempted on a blank line.

	      The  return  value is true unless	an invalid option is supplied,
	      an attempt is made to modify the options for a name for which no
	      completion specification exists, or an output error occurs.

       continue	[n]
	      Resume the next iteration	of the enclosing for, while, until, or
	      select loop.  If n is specified, resume  at  the	nth  enclosing
	      loop.   n	 must  be  >=  1.   If n is greater than the number of
	      enclosing	loops, the  last  enclosing  loop  (the	 ``top-level''
	      loop) is resumed.	 The return value is 0 unless n	is not greater
	      than or equal to 1.

       declare [-aAfFgilnrtux] [-p] [name[=value] ...]
       typeset [-aAfFgilnrtux] [-p] [name[=value] ...]
	      Declare variables	and/or give them attributes.  If no names  are
	      given  then display the values of	variables.  The	-p option will
	      display the attributes and values	of each	name.  When -p is used
	      with  name  arguments, additional	options, other than -f and -F,
	      are ignored.  When -p is supplied	 without  name	arguments,  it
	      will  display  the attributes and	values of all variables	having
	      the attributes specified by the additional options.  If no other
	      options	are   supplied	with  -p,  declare  will  display  the
	      attributes and values of all shell  variables.   The  -f	option
	      will  restrict  the  display  to shell functions.	 The -F	option
	      inhibits the display of function definitions; only the  function
	      name  and	 attributes are	printed.  If the extdebug shell	option
	      is enabled using shopt, the source file  name  and  line	number
	      where each name is defined are displayed as well.	 The -F	option
	      implies -f.  The -g option forces	variables  to  be  created  or
	      modified at the global scope, even when declare is executed in a
	      shell function.  It is ignored in	all other cases.  The  follow-
	      ing options can be used to restrict output to variables with the
	      specified	attribute or to	give variables attributes:
	      -a     Each name	is  an	indexed	 array	variable  (see	Arrays
		     above).
	      -A     Each  name	 is  an	associative array variable (see	Arrays
		     above).
	      -f     Use function names	only.
	      -i     The variable is treated as	an integer; arithmetic evalua-
		     tion  (see	ARITHMETIC EVALUATION above) is	performed when
		     the variable is assigned a	value.
	      -l     When the variable is assigned  a  value,  all  upper-case
		     characters	 are  converted	to lower-case.	The upper-case
		     attribute is disabled.
	      -n     Give each name the	nameref	attribute, making  it  a  name
		     reference	to  another  variable.	That other variable is
		     defined by	the value of name.   All  references,  assign-
		     ments,  and attribute modifications to name, except those
		     using or changing the -n attribute	itself,	are  performed
		     on	 the variable referenced by name's value.  The nameref
		     attribute cannot be applied to array variables.
	      -r     Make names	readonly.  These names cannot then be assigned
		     values by subsequent assignment statements	or unset.
	      -t     Give  each	 name  the  trace attribute.  Traced functions
		     inherit the DEBUG	and  RETURN  traps  from  the  calling
		     shell.   The  trace  attribute has	no special meaning for
		     variables.
	      -u     When the variable is assigned  a  value,  all  lower-case
		     characters	 are  converted	to upper-case.	The lower-case
		     attribute is disabled.
	      -x     Mark names	for export  to	subsequent  commands  via  the
		     environment.

	      Using  `+'  instead of `-' turns off the attribute instead, with
	      the exceptions that +a may not be	used to	destroy	an array vari-
	      able  and	 +r will not remove the	readonly attribute.  When used
	      in a function, declare and typeset make each name	local, as with
	      the local	command, unless	the -g option is supplied.  If a vari-
	      able name	is followed by =value, the value of  the  variable  is
	      set  to  value.  When using -a or	-A and the compound assignment
	      syntax to	create array variables,	additional attributes  do  not
	      take effect until	subsequent assignments.	 The return value is 0
	      unless an	invalid	option is encountered, an attempt is  made  to
	      define  a	 function  using ``-f foo=bar'', an attempt is made to
	      assign a value to	a readonly variable, an	 attempt  is  made  to
	      assign  a	 value to an array variable without using the compound
	      assignment syntax	(see Arrays above), one	of the names is	not  a
	      valid  shell variable name, an attempt is	made to	turn off read-
	      only status for a	readonly variable, an attempt is made to  turn
	      off array	status for an array variable, or an attempt is made to
	      display a	non-existent function with -f.

       dirs [-clpv] [+n] [-n]
	      Without options,	displays  the  list  of	 currently  remembered
	      directories.   The  default  display  is	on  a single line with
	      directory	names separated	by spaces.  Directories	are  added  to
	      the  list	 with  the  pushd  command;  the  popd command removes
	      entries from the list.  The  current  directory  is  always  the
	      first directory in the stack.
	      -c     Clears  the  directory  stack  by	deleting  all  of  the
		     entries.
	      -l     Produces a	listing	 using	full  pathnames;  the  default
		     listing format uses a tilde to denote the home directory.
	      -p     Print the directory stack with one	entry per line.
	      -v     Print the directory stack with one	entry per  line,  pre-
		     fixing each entry with its	index in the stack.
	      +n     Displays the nth entry counting from the left of the list
		     shown by dirs when	invoked	without	options, starting with
		     zero.
	      -n     Displays  the  nth	 entry	counting from the right	of the
		     list shown	by dirs	when invoked without options, starting
		     with zero.

	      The  return value	is 0 unless an invalid option is supplied or n
	      indexes beyond the end of	the directory stack.

       disown [-ar] [-h] [jobspec ... |	pid ...	]
	      Without options, remove each jobspec from	the  table  of	active
	      jobs.   If jobspec is not	present, and neither the -a nor	the -r
	      option is	supplied, the current job is used.  If the  -h	option
	      is  given,  each	jobspec	 is not	removed	from the table,	but is
	      marked so	that SIGHUP is not  sent  to  the  job	if  the	 shell
	      receives	a  SIGHUP.   If	 no jobspec is supplied, the -a	option
	      means to remove or mark all jobs;	the -r option without  a  job-
	      spec  argument  restricts	operation to running jobs.  The	return
	      value is 0 unless	a jobspec does not specify a valid job.

       echo [-neE] [arg	...]
	      Output the args, separated by spaces,  followed  by  a  newline.
	      The  return  status  is 0	unless a write error occurs.  If -n is
	      specified, the trailing newline is suppressed.  If the -e	option
	      is  given,  interpretation  of  the  following backslash-escaped
	      characters is enabled.  The -E option disables  the  interpreta-
	      tion  of these escape characters,	even on	systems	where they are
	      interpreted by default.  The xpg_echo shell option may  be  used
	      to  dynamically  determine  whether  or  not  echo expands these
	      escape characters	by default.  echo does	not  interpret	--  to
	      mean  the	 end of	options.  echo interprets the following	escape
	      sequences:
	      \a     alert (bell)
	      \b     backspace
	      \c     suppress further output
	      \e
	      \E     an	escape character
	      \f     form feed
	      \n     new line
	      \r     carriage return
	      \t     horizontal	tab
	      \v     vertical tab
	      \\     backslash
	      \0nnn  the eight-bit character whose value is  the  octal	 value
		     nnn (zero to three	octal digits)
	      \xHH   the  eight-bit  character	whose value is the hexadecimal
		     value HH (one or two hex digits)
	      \uHHHH the Unicode (ISO/IEC 10646) character whose value is  the
		     hexadecimal value HHHH (one to four hex digits)
	      \UHHHHHHHH
		     the  Unicode (ISO/IEC 10646) character whose value	is the
		     hexadecimal value HHHHHHHH	(one to	eight hex digits)

       enable [-a] [-dnps] [-f filename] [name ...]
	      Enable and disable builtin shell commands.  Disabling a  builtin
	      allows a disk command which has the same name as a shell builtin
	      to be executed without specifying	a full pathname,  even	though
	      the  shell  normally searches for	builtins before	disk commands.
	      If -n is used, each  name	 is  disabled;	otherwise,  names  are
	      enabled.	For example, to	use the	test binary found via the PATH
	      instead of the shell builtin version, run	 ``enable  -n  test''.
	      The  -f  option  means to	load the new builtin command name from
	      shared object filename, on systems that support dynamic loading.
	      The  -d  option will delete a builtin previously loaded with -f.
	      If no name arguments are given, or if the	-p option is supplied,
	      a	list of	shell builtins is printed.  With no other option argu-
	      ments, the list consists of all enabled shell builtins.	If  -n
	      is  supplied, only disabled builtins are printed.	 If -a is sup-
	      plied, the list printed includes all builtins, with  an  indica-
	      tion  of whether or not each is enabled.	If -s is supplied, the
	      output is	restricted to the POSIX	special	builtins.  The	return
	      value  is	 0 unless a name is not	a shell	builtin	or there is an
	      error loading a new builtin from a shared	object.

       eval [arg ...]
	      The args are read	and concatenated together into a  single  com-
	      mand.   This command is then read	and executed by	the shell, and
	      its exit status is returned as the value of eval.	 If there  are
	      no args, or only null arguments, eval returns 0.

       exec [-cl] [-a name] [command [arguments]]
	      If  command is specified,	it replaces the	shell.	No new process
	      is created.  The arguments become	the arguments to command.   If
	      the -l option is supplied, the shell places a dash at the	begin-
	      ning of the zeroth argument passed to  command.	This  is  what
	      login(1) does.  The -c option causes command to be executed with
	      an empty environment.  If	-a is supplied,	the shell passes  name
	      as the zeroth argument to	the executed command.  If command can-
	      not be executed for some reason, a non-interactive shell	exits,
	      unless  the  execfail shell option is enabled.  In that case, it
	      returns failure.	An interactive shell returns  failure  if  the
	      file cannot be executed.	If command is not specified, any redi-
	      rections take effect in the current shell, and the return	status
	      is  0.  If there is a redirection	error, the return status is 1.

       exit [n]
	      Cause the	shell to exit with a status of n.  If  n  is  omitted,
	      the exit status is that of the last command executed.  A trap on
	      EXIT is executed before the shell	terminates.

       export [-fn] [name[=word]] ...
       export -p
	      The supplied names are marked for	automatic export to the	 envi-
	      ronment  of subsequently executed	commands.  If the -f option is
	      given, the names refer to	functions.  If no names	are given,  or
	      if  the  -p  option is supplied, a list of names of all exported
	      variables	is printed.  The -n option causes the export  property
	      to be removed from each name.  If	a variable name	is followed by
	      =word, the value of the variable is set to word.	export returns
	      an exit status of	0 unless an invalid option is encountered, one
	      of the names is not a valid shell	variable name, or -f  is  sup-
	      plied with a name	that is	not a function.

       fc [-e ename] [-lnr] [first] [last]
       fc -s [pat=rep] [cmd]
	      The  first  form	selects	a range	of commands from first to last
	      from the history list and	 displays  or  edits  and  re-executes
	      them.   First  and  last may be specified	as a string (to	locate
	      the last command beginning with that string) or as a number  (an
	      index  into the history list, where a negative number is used as
	      an offset	from the current command  number).   If	 last  is  not
	      specified	 it is set to the current command for listing (so that
	      ``fc -l -10'' prints the last 10 commands) and to	 first	other-
	      wise.   If first is not specified	it is set to the previous com-
	      mand for editing and -16 for listing.

	      The -n option suppresses the command numbers when	listing.   The
	      -r  option reverses the order of the commands.  If the -l	option
	      is given,	the commands are listed	on  standard  output.	Other-
	      wise,  the editor	given by ename is invoked on a file containing
	      those commands.  If ename	is not given, the value	of the	FCEDIT
	      variable	is used, and the value of EDITOR if FCEDIT is not set.
	      If neither variable is set, vi is	used.  When  editing  is  com-
	      plete, the edited	commands are echoed and	executed.

	      In  the  second form, command is re-executed after each instance
	      of pat is	replaced by rep.  Command is intepreted	 the  same  as
	      first  above.  A useful alias to use with	this is	``r="fc	-s"'',
	      so that typing ``r cc'' runs the	last  command  beginning  with
	      ``cc'' and typing	``r'' re-executes the last command.

	      If  the  first  form  is	used,  the return value	is 0 unless an
	      invalid option is	encountered or first or	last  specify  history
	      lines  out  of  range.  If the -e	option is supplied, the	return
	      value is the value of the	last command executed or failure if an
	      error occurs with	the temporary file of commands.	 If the	second
	      form is used, the	return status is that of the  command  re-exe-
	      cuted,  unless  cmd  does	 not  specify a	valid history line, in
	      which case fc returns failure.

       fg [jobspec]
	      Resume jobspec in	the foreground,	and make it the	 current  job.
	      If jobspec is not	present, the shell's notion of the current job
	      is used.	The return value is that of the	 command  placed  into
	      the  foreground,	or failure if run when job control is disabled
	      or, when run with	job control enabled, if	jobspec	does not spec-
	      ify  a  valid  job  or  jobspec specifies	a job that was started
	      without job control.

       getopts optstring name [args]
	      getopts is used by shell procedures to parse positional  parame-
	      ters.   optstring	 contains  the	option characters to be	recog-
	      nized; if	a character is followed	by  a  colon,  the  option  is
	      expected	to have	an argument, which should be separated from it
	      by white space.  The colon and question mark characters may  not
	      be  used as option characters.  Each time	it is invoked, getopts
	      places the next option in	the shell variable name,  initializing
	      name if it does not exist, and the index of the next argument to
	      be processed into	the variable OPTIND.  OPTIND is	initialized to
	      1	 each  time  the  shell	or a shell script is invoked.  When an
	      option requires an argument, getopts places that	argument  into
	      the  variable OPTARG.  The shell does not	reset OPTIND automati-
	      cally; it	must be	 manually  reset  between  multiple  calls  to
	      getopts within the same shell invocation if a new	set of parame-
	      ters is to be used.

	      When the end of options is encountered,  getopts	exits  with  a
	      return  value  greater than zero.	 OPTIND	is set to the index of
	      the first	non-option argument, and name is set to	?.

	      getopts normally parses the positional parameters, but  if  more
	      arguments	are given in args, getopts parses those	instead.

	      getopts  can  report errors in two ways.	If the first character
	      of optstring is a	colon, silent error  reporting	is  used.   In
	      normal  operation,  diagnostic messages are printed when invalid
	      options or missing option	arguments  are	encountered.   If  the
	      variable	OPTERR	is  set	 to  0,	no error messages will be dis-
	      played, even if the first	character of optstring is not a	colon.

	      If an invalid option is seen, getopts places ? into name and, if
	      not silent, prints an  error  message  and  unsets  OPTARG.   If
	      getopts  is  silent,  the	 option	 character  found is placed in
	      OPTARG and no diagnostic message is printed.

	      If a required argument is	not found, and getopts is not  silent,
	      a	 question  mark	 (?) is	placed in name,	OPTARG is unset, and a
	      diagnostic message is printed.  If getopts  is  silent,  then  a
	      colon  (:)  is  placed  in  name and OPTARG is set to the	option
	      character	found.

	      getopts returns true if an option, specified or unspecified,  is
	      found.  It returns false if the end of options is	encountered or
	      an error occurs.

       hash [-lr] [-p filename]	[-dt] [name]
	      Each time	hash is	invoked, the full pathname of the command name
	      is  determined  by searching the directories in $PATH and	remem-
	      bered.  Any previously-remembered	pathname is discarded.	If the
	      -p option	is supplied, no	path search is performed, and filename
	      is used as the full filename of  the  command.   The  -r	option
	      causes  the  shell  to  forget all remembered locations.	The -d
	      option causes the	shell to forget	 the  remembered  location  of
	      each  name.   If the -t option is	supplied, the full pathname to
	      which each name corresponds is printed.  If multiple name	 argu-
	      ments  are  supplied  with  -t,  the  name is printed before the
	      hashed full pathname.  The -l option causes output  to  be  dis-
	      played in	a format that may be reused as input.  If no arguments
	      are given, or if only -l is supplied, information	 about	remem-
	      bered  commands  is printed.  The	return status is true unless a
	      name is not found	or an invalid option is	supplied.

       help [-dms] [pattern]
	      Display helpful information about	builtin	commands.  If  pattern
	      is  specified, help gives	detailed help on all commands matching
	      pattern; otherwise help for all the builtins and	shell  control
	      structures is printed.
	      -d     Display a short description of each pattern
	      -m     Display the description of	each pattern in	a manpage-like
		     format
	      -s     Display only a short usage	synopsis for each pattern

	      The return status	is 0 unless no command matches pattern.

       history [n]
       history -c
       history -d offset
       history -anrw [filename]
       history -p arg [arg ...]
       history -s arg [arg ...]
	      With no options, display the command history list	with line num-
	      bers.  Lines listed with a * have	been modified.	An argument of
	      n	lists only the last n lines.  If the shell variable  HISTTIME-
	      FORMAT  is  set  and not null, it	is used	as a format string for
	      strftime(3) to display the time stamp associated with each  dis-
	      played  history  entry.  No intervening blank is printed between
	      the formatted time stamp and the history line.  If  filename  is
	      supplied,	 it  is	 used as the name of the history file; if not,
	      the value	of HISTFILE is used.  Options, if supplied,  have  the
	      following	meanings:
	      -c     Clear the history list by deleting	all the	entries.
	      -d offset
		     Delete the	history	entry at position offset.
	      -a     Append  the  ``new''  history  lines to the history file.
		     These are history lines entered since  the	 beginning  of
		     the current bash session, but not already appended	to the
		     history file.
	      -n     Read the history lines not	already	read from the  history
		     file  into	 the  current  history	list.  These are lines
		     appended to the history file since	the beginning  of  the
		     current bash session.
	      -r     Read  the contents	of the history file and	append them to
		     the current history list.
	      -w     Write the current history list to the history file, over-
		     writing the history file's	contents.
	      -p     Perform  history  substitution  on	the following args and
		     display the result	on  the	 standard  output.   Does  not
		     store  the	results	in the history list.  Each arg must be
		     quoted to disable normal history expansion.
	      -s     Store the args in the history list	 as  a	single	entry.
		     The  last	command	 in the	history	list is	removed	before
		     the args are added.

	      If the HISTTIMEFORMAT variable is	set, the time  stamp  informa-
	      tion  associated	with each history entry	is written to the his-
	      tory file, marked	with the history comment character.  When  the
	      history  file  is	read, lines beginning with the history comment
	      character	followed immediately by	a  digit  are  interpreted  as
	      timestamps for the following history entry.  The return value is
	      0	unless an invalid option is encountered, an error occurs while
	      reading  or  writing the history file, an	invalid	offset is sup-
	      plied as an argument to -d, or the history expansion supplied as
	      an argument to -p	fails.

       jobs [-lnprs] [ jobspec ... ]
       jobs -x command [ args ... ]
	      The first	form lists the active jobs.  The options have the fol-
	      lowing meanings:
	      -l     List process IDs in addition to the normal	information.
	      -n     Display information only about  jobs  that	 have  changed
		     status  since the user was	last notified of their status.
	      -p     List only the process  ID	of  the	 job's	process	 group
		     leader.
	      -r     Display only running jobs.
	      -s     Display only stopped jobs.

	      If  jobspec  is given, output is restricted to information about
	      that job.	 The return status is 0	unless an  invalid  option  is
	      encountered or an	invalid	jobspec	is supplied.

	      If the -x	option is supplied, jobs replaces any jobspec found in
	      command or args with the corresponding  process  group  ID,  and
	      executes command passing it args,	returning its exit status.

       kill [-s	sigspec	| -n signum | -sigspec]	[pid | jobspec]	...
       kill -l|-L [sigspec | exit_status]
	      Send  the	 signal	 named	by  sigspec or signum to the processes
	      named by pid or jobspec.	sigspec	is either  a  case-insensitive
	      signal  name such	as SIGKILL (with or without the	SIG prefix) or
	      a	signal number; signum is a signal number.  If sigspec  is  not
	      present,	then  SIGTERM is assumed.  An argument of -l lists the
	      signal names.  If	any arguments are supplied when	-l  is	given,
	      the  names  of  the  signals  corresponding to the arguments are
	      listed, and the return status is 0.  The exit_status argument to
	      -l  is  a	 number	 specifying either a signal number or the exit
	      status of	a process terminated by	a signal.  The	-L  option  is
	      equivalent  to -l.  kill returns true if at least	one signal was
	      successfully sent, or false if an	error  occurs  or  an  invalid
	      option is	encountered.

       let arg [arg ...]
	      Each arg is an arithmetic	expression to be evaluated (see	ARITH-
	      METIC EVALUATION above).	If the last arg	evaluates  to  0,  let
	      returns 1; 0 is returned otherwise.

       local [option] [name[=value] ...	| - ]
	      For  each	 argument, a local variable named name is created, and
	      assigned value.  The option can be any of	the  options  accepted
	      by declare.  When	local is used within a function, it causes the
	      variable name to have a visible scope restricted to  that	 func-
	      tion  and	 its children.	If name	is -, the set of shell options
	      is made local to the function in which local is  invoked:	 shell
	      options  changed	using  the set builtin inside the function are
	      restored to their	original values	 when  the  function  returns.
	      With  no operands, local writes a	list of	local variables	to the
	      standard output.	It is an error to use local when not within  a
	      function.	 The return status is 0	unless local is	used outside a
	      function,	an invalid name	is supplied, or	 name  is  a  readonly
	      variable.

       logout Exit a login shell.

       mapfile	[-d  delim] [-n	count] [-O origin] [-s count] [-t] [-u fd] [-C
       callback] [-c quantum] [array]
       readarray [-d delim] [-n	count] [-O origin] [-s count] [-t] [-u fd] [-C
       callback] [-c quantum] [array]
	      Read  lines from the standard input into the indexed array vari-
	      able array, or from file descriptor fd if	the -u option is  sup-
	      plied.   The variable MAPFILE is the default array.  Options, if
	      supplied,	have the following meanings:
	      -d     The first character of delim is used  to  terminate  each
		     input line, rather	than newline.
	      -n     Copy  at  most count lines.  If count is 0, all lines are
		     copied.
	      -O     Begin assigning to	array at index	origin.	  The  default
		     index is 0.
	      -s     Discard the first count lines read.
	      -t     Remove  a trailing	delim (default newline)	from each line
		     read.
	      -u     Read lines	from file descriptor fd	instead	of  the	 stan-
		     dard input.
	      -C     Evaluate  callback	each time quantum lines	are read.  The
		     -c	option specifies quantum.
	      -c     Specify the number	of lines read  between	each  call  to
		     callback.

	      If  -C  is  specified  without  -c, the default quantum is 5000.
	      When callback is evaluated, it is	supplied the index of the next
	      array element to be assigned and the line	to be assigned to that
	      element as additional arguments.	callback  is  evaluated	 after
	      the line is read but before the array element is assigned.

	      If  not  supplied	 with  an  explicit origin, mapfile will clear
	      array before assigning to	it.

	      mapfile returns successfully unless an invalid option or	option
	      argument	is  supplied,  array is	invalid	or unassignable, or if
	      array is not an indexed array.

       popd [-n] [+n] [-n]
	      Removes entries from the directory stack.	  With	no  arguments,
	      removes  the  top	directory from the stack, and performs a cd to
	      the new top directory.  Arguments, if supplied, have the follow-
	      ing meanings:
	      -n     Suppresses	 the  normal change of directory when removing
		     directories from the stack, so that  only	the  stack  is
		     manipulated.
	      +n     Removes  the nth entry counting from the left of the list
		     shown by dirs, starting with zero.	 For  example:	``popd
		     +0'' removes the first directory, ``popd +1'' the second.
	      -n     Removes the nth entry counting from the right of the list
		     shown  by	dirs, starting with zero.  For example:	``popd
		     -0'' removes the last directory, ``popd -1'' the next  to
		     last.

	      If  the popd command is successful, a dirs is performed as well,
	      and the return status is 0.  popd	returns	false  if  an  invalid
	      option is	encountered, the directory stack is empty, a non-exis-
	      tent directory stack entry is specified, or the directory	change
	      fails.

       printf [-v var] format [arguments]
	      Write  the  formatted arguments to the standard output under the
	      control of the format.  The -v option causes the	output	to  be
	      assigned	to  the	 variable var rather than being	printed	to the
	      standard output.

	      The format is a character	string which contains three  types  of
	      objects:	plain  characters, which are simply copied to standard
	      output, character	escape	sequences,  which  are	converted  and
	      copied  to  the standard output, and format specifications, each
	      of which causes printing of the next  successive	argument.   In
	      addition to the standard printf(1) format	specifications,	printf
	      interprets the following extensions:
	      %b     causes printf to expand backslash escape sequences	in the
		     corresponding argument in the same	way as echo -e.
	      %q     causes  printf  to	output the corresponding argument in a
		     format that can be	reused as shell	input.
	      %(datefmt)T
		     causes printf to output the  date-time  string  resulting
		     from  using  datefmt  as a	format string for strftime(3).
		     The corresponding argument	is an integer representing the
		     number  of	seconds	since the epoch.  Two special argument
		     values may	be used: -1 represents the current  time,  and
		     -2	 represents  the  time	the  shell was invoked.	 If no
		     argument is specified, conversion behaves as  if  -1  had
		     been  given.   This  is  an exception to the usual	printf
		     behavior.

	      Arguments	to non-string format specifiers	are treated as C  con-
	      stants, except that a leading plus or minus sign is allowed, and
	      if the leading character is a single or double quote, the	 value
	      is the ASCII value of the	following character.

	      The  format  is  reused as necessary to consume all of the argu-
	      ments.  If the format requires more arguments than are supplied,
	      the  extra  format  specifications  behave as if a zero value or
	      null string, as appropriate,  had	 been  supplied.   The	return
	      value is zero on success,	non-zero on failure.

       pushd [-n] [+n] [-n]
       pushd [-n] [dir]
	      Adds  a  directory to the	top of the directory stack, or rotates
	      the stack, making	the new	top of the stack the  current  working
	      directory.   With	 no  arguments,	 pushd	exchanges  the top two
	      directories and returns 0, unless	the directory stack is	empty.
	      Arguments, if supplied, have the following meanings:
	      -n     Suppresses	 the  normal change of directory when rotating
		     or	adding directories to the  stack,  so  that  only  the
		     stack is manipulated.
	      +n     Rotates  the  stack  so  that the nth directory (counting
		     from the left of the list shown by	 dirs,	starting  with
		     zero) is at the top.
	      -n     Rotates  the  stack  so  that the nth directory (counting
		     from the right of the list	shown by dirs,	starting  with
		     zero) is at the top.
	      dir    Adds dir to the directory stack at	the top, making	it the
		     new current working directory as if it had	been  supplied
		     as	the argument to	the cd builtin.

	      If the pushd command is successful, a dirs is performed as well.
	      If the first form	is used, pushd returns 0 unless	the cd to  dir
	      fails.   With the	second form, pushd returns 0 unless the	direc-
	      tory stack is empty, a non-existent directory stack  element  is
	      specified,  or the directory change to the specified new current
	      directory	fails.

       pwd [-LP]
	      Print the	absolute pathname of the  current  working  directory.
	      The pathname printed contains no symbolic	links if the -P	option
	      is supplied or the -o physical option to the set builtin command
	      is  enabled.  If the -L option is	used, the pathname printed may
	      contain symbolic links.  The return status is 0 unless an	 error
	      occurs  while  reading  the  name	of the current directory or an
	      invalid option is	supplied.

       read [-ers] [-a aname] [-d delim] [-i text] [-n nchars] [-N nchars] [-p
       prompt] [-t timeout] [-u	fd] [name ...]
	      One line is read from the	 standard  input,  or  from  the  file
	      descriptor  fd  supplied	as an argument to the -u option, split
	      into words as described above  under  Word  Splitting,  and  the
	      first word is assigned to	the first name,	the second word	to the
	      second name, and so on.  If there	are more words than names, the
	      remaining	words and their	intervening delimiters are assigned to
	      the last name.  If there are fewer words	read  from  the	 input
	      stream  than  names, the remaining names are assigned empty val-
	      ues.  The	characters in IFS are used  to	split  the  line  into
	      words  using  the	 same  rules  the  shell  uses	for  expansion
	      (described above under Word Splitting).  The backslash character
	      (\) may be used to remove	any special meaning for	the next char-
	      acter read and for line  continuation.   Options,	 if  supplied,
	      have the following meanings:
	      -a aname
		     The words are assigned to sequential indices of the array
		     variable aname, starting at 0.  aname is unset before any
		     new  values  are  assigned.   Other  name	arguments  are
		     ignored.
	      -d delim
		     The first character of delim is  used  to	terminate  the
		     input line, rather	than newline.
	      -e     If	the standard input is coming from a terminal, readline
		     (see READLINE above) is used to obtain the	 line.	 Read-
		     line  uses	 the  current (or default, if line editing was
		     not previously active) editing settings.
	      -i text
		     If	readline is being used	to  read  the  line,  text  is
		     placed into the editing buffer before editing begins.
	      -n nchars
		     read  returns after reading nchars	characters rather than
		     waiting for a complete line of input, but honors a	delim-
		     iter  if fewer than nchars	characters are read before the
		     delimiter.
	      -N nchars
		     read returns  after  reading  exactly  nchars  characters
		     rather  than waiting for a	complete line of input,	unless
		     EOF is encountered	or read	times out.  Delimiter  charac-
		     ters  encountered	in the input are not treated specially
		     and do not	cause read to return until  nchars  characters
		     are  read.	  The result is	not split on the characters in
		     IFS; the intent is	that the variable is assigned  exactly
		     the characters read (with the exception of	backslash; see
		     the -r option below).
	      -p prompt
		     Display prompt on standard	error, without a trailing new-
		     line, before attempting to	read any input.	 The prompt is
		     displayed only if input is	coming from a terminal.
	      -r     Backslash does not	act as an escape character.  The back-
		     slash  is considered to be	part of	the line.  In particu-
		     lar, a backslash-newline pair may not be used as  a  line
		     continuation.
	      -s     Silent mode.  If input is coming from a terminal, charac-
		     ters are not echoed.
	      -t timeout
		     Cause read	to time	out and	return failure if  a  complete
		     line  of  input  (or a specified number of	characters) is
		     not read within timeout seconds.  timeout may be a	 deci-
		     mal  number with a	fractional portion following the deci-
		     mal point.	 This option is	 only  effective  if  read  is
		     reading  input  from  a  terminal,	pipe, or other special
		     file; it has no effect when reading from  regular	files.
		     If	read times out,	read saves any partial input read into
		     the specified variable  name.   If	 timeout  is  0,  read
		     returns  immediately,  without  trying  to	read any data.
		     The exit status is	0 if input is available	on the	speci-
		     fied  file	descriptor, non-zero otherwise.	 The exit sta-
		     tus is greater than 128 if	the timeout is exceeded.
	      -u fd  Read input	from file descriptor fd.

	      If no names are supplied,	the line read is assigned to the vari-
	      able  REPLY.   The  exit	status	is zero, unless	end-of-file is
	      encountered, read	times out (in which case the status is greater
	      than  128),  a variable assignment error (such as	assigning to a
	      readonly variable) occurs, or an invalid file descriptor is sup-
	      plied as the argument to -u.

       readonly	[-aAf] [-p] [name[=word] ...]
	      The  given  names	are marked readonly; the values	of these names
	      may not be changed by subsequent assignment.  If the  -f	option
	      is  supplied,  the  functions  corresponding to the names	are so
	      marked.  The  -a	option	restricts  the	variables  to  indexed
	      arrays;  the  -A	option	restricts the variables	to associative
	      arrays.  If both options are supplied, -A	takes precedence.   If
	      no  name arguments are given, or if the -p option	is supplied, a
	      list of all readonly names is printed.  The other	options	may be
	      used  to	restrict the output to a subset	of the set of readonly
	      names.  The -p option causes output to be	displayed in a	format
	      that  may	be reused as input.  If	a variable name	is followed by
	      =word, the value of the variable is set  to  word.   The	return
	      status  is 0 unless an invalid option is encountered, one	of the
	      names is not a valid shell variable name,	or -f is supplied with
	      a	name that is not a function.

       return [n]
	      Causes  a	function to stop executing and return the value	speci-
	      fied by n	to its caller.	If n is	omitted, the return status  is
	      that  of	the  last  command  executed in	the function body.  If
	      return is	executed by a trap handler, the	last command  used  to
	      determine	 the  status  is  the last command executed before the
	      trap handler.  if	return is executed during a  DEBUG  trap,  the
	      last  command  used  to determine	the status is the last command
	      executed by the trap handler  before  return  was	 invoked.   If
	      return  is  used	outside	 a function, but during	execution of a
	      script by	the .  (source)	command, it causes the shell  to  stop
	      executing	 that script and return	either n or the	exit status of
	      the last command executed	within the script as the  exit	status
	      of  the script.  If n is supplied, the return value is its least
	      significant 8 bits.  The return status is	non-zero if return  is
	      supplied	a  non-numeric argument, or is used outside a function
	      and not during execution of a script by .	or source.   Any  com-
	      mand  associated	with the RETURN	trap is	executed before	execu-
	      tion resumes after the function or script.

       set [--abefhkmnptuvxBCEHPT] [-o option-name] [arg ...]
       set [+abefhkmnptuvxBCEHPT] [+o option-name] [arg	...]
	      Without options, the name	and value of each shell	 variable  are
	      displayed	in a format that can be	reused as input	for setting or
	      resetting	the currently-set variables.  Read-only	variables can-
	      not  be  reset.  In posix	mode, only shell variables are listed.
	      The output is sorted according  to  the  current	locale.	  When
	      options  are specified, they set or unset	shell attributes.  Any
	      arguments	remaining after	option processing are treated as  val-
	      ues for the positional parameters	and are	assigned, in order, to
	      $1, $2, ...  $n.	Options,  if  specified,  have	the  following
	      meanings:
	      -a      Each variable or function	that is	created	or modified is
		      given the	export attribute and marked for	export to  the
		      environment of subsequent	commands.
	      -b      Report  the status of terminated background jobs immedi-
		      ately, rather than before	the next primary prompt.  This
		      is effective only	when job control is enabled.
	      -e      Exit  immediately	 if a pipeline (which may consist of a
		      single simple command), a	list, or  a  compound  command
		      (see SHELL GRAMMAR above), exits with a non-zero status.
		      The shell	does not exit if the  command  that  fails  is
		      part  of	the command list immediately following a while
		      or until keyword,	part of	the test following the	if  or
		      elif  reserved  words, part of any command executed in a
		      && or || list except the command following the final  &&
		      or ||, any command in a pipeline but the last, or	if the
		      command's	return value is	being inverted with !.	 If  a
		      compound	command	 other	than a subshell	returns	a non-
		      zero status because a command failed while -e was	 being
		      ignored,	the  shell  does  not exit.  A trap on ERR, if
		      set, is executed before the shell	 exits.	  This	option
		      applies to the shell environment and each	subshell envi-
		      ronment separately (see  COMMAND	EXECUTION  ENVIRONMENT
		      above), and may cause subshells to exit before executing
		      all the commands in the subshell.

		      If a compound command or shell function  executes	 in  a
		      context  where -e	is being ignored, none of the commands
		      executed within the compound command  or	function  body
		      will  be	affected  by the -e setting, even if -e	is set
		      and a command returns a failure status.  If  a  compound
		      command  or  shell function sets -e while	executing in a
		      context where -e is ignored, that	setting	will not  have
		      any  effect  until  the  compound	command	or the command
		      containing the function call completes.
	      -f      Disable pathname expansion.
	      -h      Remember the location of commands	as they	are looked  up
		      for execution.  This is enabled by default.
	      -k      All  arguments  in the form of assignment	statements are
		      placed in	the environment	for a command, not just	 those
		      that precede the command name.
	      -m      Monitor  mode.   Job control is enabled.	This option is
		      on by default for	interactive  shells  on	 systems  that
		      support  it  (see	JOB CONTROL above).  All processes run
		      in a separate process group.  When a background job com-
		      pletes, the shell	prints a line containing its exit sta-
		      tus.
	      -n      Read commands but	do not execute them.  This may be used
		      to  check	 a  shell  script  for syntax errors.  This is
		      ignored by interactive shells.
	      -o option-name
		      The option-name can be one of the	following:
		      allexport
			      Same as -a.
		      braceexpand
			      Same as -B.
		      emacs   Use an emacs-style command line  editing	inter-
			      face.  This is enabled by	default	when the shell
			      is interactive, unless the shell is started with
			      the  --noediting	option.	 This also affects the
			      editing interface	used for read -e.
		      errexit Same as -e.
		      errtrace
			      Same as -E.
		      functrace
			      Same as -T.
		      hashall Same as -h.
		      histexpand
			      Same as -H.
		      history Enable command history, as described above under
			      HISTORY.	This option is on by default in	inter-
			      active shells.
		      ignoreeof
			      The  effect  is  as   if	 the   shell   command
			      ``IGNOREEOF=10''	had  been  executed (see Shell
			      Variables	above).
		      keyword Same as -k.
		      monitor Same as -m.
		      noclobber
			      Same as -C.
		      noexec  Same as -n.
		      noglob  Same as -f.
		      nolog   Currently	ignored.
		      notify  Same as -b.
		      nounset Same as -u.
		      onecmd  Same as -t.
		      physical
			      Same as -P.
		      pipefail
			      If set, the return value of a  pipeline  is  the
			      value  of	 the  last (rightmost) command to exit
			      with a non-zero status, or zero if all  commands
			      in  the pipeline exit successfully.  This	option
			      is disabled by default.
		      posix   Change the behavior of bash  where  the  default
			      operation	 differs  from	the  POSIX standard to
			      match the	standard (posix	mode).	See  SEE  ALSO
			      below for	a reference to a document that details
			      how posix	mode affects bash's behavior.
		      privileged
			      Same as -p.
		      verbose Same as -v.
		      vi      Use a vi-style command line  editing  interface.
			      This also	affects	the editing interface used for
			      read -e.
		      xtrace  Same as -x.
		      If -o is supplied	with no	option-name, the values	of the
		      current  options are printed.  If	+o is supplied with no
		      option-name, a series of set commands  to	 recreate  the
		      current  option  settings	 is  displayed on the standard
		      output.
	      -p      Turn on privileged mode.	In this	 mode,	the  $ENV  and
		      $BASH_ENV	 files	are not	processed, shell functions are
		      not inherited from the environment, and  the  SHELLOPTS,
		      BASHOPTS,	 CDPATH,  and  GLOBIGNORE  variables,  if they
		      appear in	the environment, are ignored.  If the shell is
		      started  with the	effective user (group) id not equal to
		      the real user (group) id,	and the	-p option is not  sup-
		      plied, these actions are taken and the effective user id
		      is set to	the real user id.  If the -p  option  is  sup-
		      plied  at	 startup,  the effective user id is not	reset.
		      Turning this option off causes the  effective  user  and
		      group ids	to be set to the real user and group ids.
	      -t      Exit after reading and executing one command.
	      -u      Treat unset variables and	parameters other than the spe-
		      cial parameters "@" and "*" as an	error when  performing
		      parameter	 expansion.   If  expansion is attempted on an
		      unset variable or	parameter, the shell prints  an	 error
		      message,	and, if	not interactive, exits with a non-zero
		      status.
	      -v      Print shell input	lines as they are read.
	      -x      After expanding each simple command, for	command,  case
		      command, select command, or arithmetic for command, dis-
		      play the expanded	value of PS4, followed by the  command
		      and its expanded arguments or associated word list.
	      -B      The  shell performs brace	expansion (see Brace Expansion
		      above).  This is on by default.
	      -C      If set, bash does	not overwrite an  existing  file  with
		      the  >,  >&,  and	<> redirection operators.  This	may be
		      overridden when creating output files by using the redi-
		      rection operator >| instead of >.
	      -E      If set, any trap on ERR is inherited by shell functions,
		      command substitutions, and commands executed in  a  sub-
		      shell  environment.  The ERR trap	is normally not	inher-
		      ited in such cases.
	      -H      Enable !	style history substitution.  This option is on
		      by default when the shell	is interactive.
	      -P      If  set,	the shell does not resolve symbolic links when
		      executing	commands such as cd that  change  the  current
		      working  directory.   It	uses  the  physical  directory
		      structure	instead.  By default, bash follows the logical
		      chain  of	 directories  when  performing	commands which
		      change the current directory.
	      -T      If set, any traps	on DEBUG and RETURN are	 inherited  by
		      shell  functions,	 command  substitutions,  and commands
		      executed in  a  subshell	environment.   The  DEBUG  and
		      RETURN traps are normally	not inherited in such cases.
	      --      If  no arguments follow this option, then	the positional
		      parameters are unset.  Otherwise,	the positional parame-
		      ters  are	 set  to  the args, even if some of them begin
		      with a -.
	      -	      Signal the end of	options, cause all remaining  args  to
		      be assigned to the positional parameters.	 The -x	and -v
		      options are turned off.  If there	are no args, the posi-
		      tional parameters	remain unchanged.

	      The  options are off by default unless otherwise noted.  Using +
	      rather than - causes  these  options  to	be  turned  off.   The
	      options  can  also be specified as arguments to an invocation of
	      the shell.  The current set of options may be found in $-.   The
	      return status is always true unless an invalid option is encoun-
	      tered.

       shift [n]
	      The positional parameters	from n+1 ... are renamed  to  $1  ....
	      Parameters  represented  by  the	numbers	 $# down to $#-n+1 are
	      unset.  n	must be	a non-negative number less than	 or  equal  to
	      $#.   If	n is 0,	no parameters are changed.  If n is not	given,
	      it is assumed to be 1.  If n is greater than $#, the  positional
	      parameters  are  not changed.  The return	status is greater than
	      zero if n	is greater than	$# or less than	zero; otherwise	0.

       shopt [-pqsu] [-o] [optname ...]
	      Toggle the values	of settings controlling	optional shell	behav-
	      ior.   The settings can be either	those listed below, or,	if the
	      -o option	is used, those available with the -o option to the set
	      builtin command.	With no	options, or with the -p	option,	a list
	      of all settable options is  displayed,  with  an	indication  of
	      whether  or  not each is set.  The -p option causes output to be
	      displayed	in a form that may be reused as	input.	Other  options
	      have the following meanings:
	      -s     Enable (set) each optname.
	      -u     Disable (unset) each optname.
	      -q     Suppresses	 normal	output (quiet mode); the return	status
		     indicates whether the optname is set or unset.  If	multi-
		     ple  optname arguments are	given with -q, the return sta-
		     tus is zero if all	optnames are enabled; non-zero	other-
		     wise.
	      -o     Restricts	the  values of optname to be those defined for
		     the -o option to the set builtin.

	      If either	-s or -u is used  with	no  optname  arguments,	 shopt
	      shows  only  those options which are set or unset, respectively.
	      Unless otherwise noted, the shopt	options	are  disabled  (unset)
	      by default.

	      The  return  status when listing options is zero if all optnames
	      are enabled, non-zero  otherwise.	  When	setting	 or  unsetting
	      options,	the  return  status is zero unless an optname is not a
	      valid shell option.

	      The list of shopt	options	is:

	      autocd  If set, a	command	name that is the name of  a  directory
		      is  executed  as	if it were the argument	to the cd com-
		      mand.  This option is only used by interactive shells.
	      cdable_vars
		      If set, an argument to the cd builtin  command  that  is
		      not  a directory is assumed to be	the name of a variable
		      whose value is the directory to change to.
	      cdspell If set, minor errors in the spelling of a	directory com-
		      ponent  in  a  cd	command	will be	corrected.  The	errors
		      checked for are transposed characters, a missing charac-
		      ter,  and	 one  character	 too many.  If a correction is
		      found, the corrected filename is printed,	and  the  com-
		      mand  proceeds.  This option is only used	by interactive
		      shells.
	      checkhash
		      If set, bash checks that a command found in the hash ta-
		      ble  exists  before  trying  to execute it.  If a	hashed
		      command no longer	exists,	a normal path search  is  per-
		      formed.
	      checkjobs
		      If set, bash lists the status of any stopped and running
		      jobs before exiting an interactive shell.	 If  any  jobs
		      are running, this	causes the exit	to be deferred until a
		      second exit is attempted without an intervening  command
		      (see  JOB	 CONTROL  above).   The	shell always postpones
		      exiting if any jobs are stopped.
	      checkwinsize
		      If set, bash checks the window size after	 each  command
		      and,  if necessary, updates the values of	LINES and COL-
		      UMNS.
	      cmdhist If set, bash attempts to save all	lines of  a  multiple-
		      line  command  in	 the  same history entry.  This	allows
		      easy re-editing of multi-line commands.
	      colonbreakswords
		      If set, and readline is being used, bash will treat : as
		      separating  word	being  completed (see Completing under
		      READLINE above).	This is	enabled	by default.
	      compat31
		      If set, bash changes its behavior	to that	of version 3.1
		      with  respect  to	quoted arguments to the	[[ conditional
		      command's	=~ operator and	locale-specific	string compar-
		      ison  when  using	 the  [[ conditional command's < and >
		      operators.  Bash versions	prior to  bash-4.1  use	 ASCII
		      collation	and strcmp(3); bash-4.1	and later use the cur-
		      rent locale's collation sequence and strcoll(3).
	      compat32
		      If set, bash changes its behavior	to that	of version 3.2
		      with  respect  to	locale-specific	string comparison when
		      using the	[[ conditional command's  <  and  >  operators
		      (see  previous  item)  and  the effect of	interrupting a
		      command list.  Bash versions 3.2	and  earlier  continue
		      with  the	 next command in the list after	one terminates
		      due to an	interrupt.
	      compat40
		      If set, bash changes its behavior	to that	of version 4.0
		      with  respect  to	locale-specific	string comparison when
		      using the	[[ conditional command's  <  and  >  operators
		      (see  description	 of compat31) and the effect of	inter-
		      rupting a	command	list.  Bash  versions  4.0  and	 later
		      interrupt	 the  list as if the shell received the	inter-
		      rupt; previous versions continue with the	 next  command
		      in the list.
	      compat41
		      If  set, bash, when in posix mode, treats	a single quote
		      in a double-quoted  parameter  expansion	as  a  special
		      character.   The	single quotes must match (an even num-
		      ber) and the characters between the  single  quotes  are
		      considered  quoted.   This is the	behavior of posix mode
		      through version 4.1.  The	default	bash behavior  remains
		      as in previous versions.
	      compat42
		      If  set, bash does not process the replacement string in
		      the pattern  substitution	 word  expansion  using	 quote
		      removal.
	      compat43
		      If  set,	bash  does  not	 print a warning message if an
		      attempt is made to use a quoted compound	array  assign-
		      ment  as	an  argument  to declare, makes	word expansion
		      errors non-fatal errors that cause the  current  command
		      to  fail	(the  default  behavior	 is to make them fatal
		      errors that cause	the shell to exit), and	does not reset
		      the  loop	 state when a shell function is	executed (this
		      allows break or continue in a shell function  to	affect
		      loops in the caller's context).
	      complete_fullquote
		      If  set,	bash  quotes all shell metacharacters in file-
		      names and	directory names	 when  performing  completion.
		      If not set, bash removes metacharacters such as the dol-
		      lar sign from the	set of characters that will be	quoted
		      in  completed filenames when these metacharacters	appear
		      in shell variable	references in words to	be  completed.
		      This  means  that	 dollar	 signs	in variable names that
		      expand to	directories will not be	quoted;	 however,  any
		      dollar  signs appearing in filenames will	not be quoted,
		      either.  This is active only when	bash  is  using	 back-
		      slashes  to quote	completed filenames.  This variable is
		      set by default, which is the default  bash  behavior  in
		      versions through 4.2.
	      direxpand
		      If  set,	bash replaces directory	names with the results
		      of word expansion	when performing	 filename  completion.
		      This  changes  the  contents  of	the  readline  editing
		      buffer.  If not set, bash	attempts to preserve what  the
		      user typed.
	      dirspell
		      If  set,	bash attempts spelling correction on directory
		      names during word	completion if the directory name  ini-
		      tially supplied does not exist.
	      dotglob If  set, bash includes filenames beginning with a	`.' in
		      the results of pathname expansion.
	      execfail
		      If set, a	non-interactive	shell will not exit if it can-
		      not  execute  the	 file  specified as an argument	to the
		      exec builtin command.  An	 interactive  shell  does  not
		      exit if exec fails.
	      expand_aliases
		      If  set,	aliases	 are expanded as described above under
		      ALIASES.	This option is enabled by default for interac-
		      tive shells.
	      extdebug
		      If  set  at  shell  invocation,  arrange	to execute the
		      debugger profile before the shell	starts,	 identical  to
		      the  --debugger option.  If set after invocation,	behav-
		      ior intended for use by debuggers	is enabled:
		      1.     The -F option to the declare builtin displays the
			     source file name and line number corresponding to
			     each function name	supplied as an argument.
		      2.     If	the command run	by the DEBUG  trap  returns  a
			     non-zero  value,  the next	command	is skipped and
			     not executed.
		      3.     If	the command run	by the DEBUG  trap  returns  a
			     value  of 2, and the shell	is executing in	a sub-
			     routine (a	shell function or a shell script  exe-
			     cuted  by	the  .	or source builtins), the shell
			     simulates a call to return.
		      4.     BASH_ARGC and BASH_ARGV are updated as  described
			     in	their descriptions above.
		      5.     Function  tracing	is  enabled: command substitu-
			     tion, shell functions, and	subshells invoked with
			     ( command ) inherit the DEBUG and RETURN traps.
		      6.     Error  tracing  is	enabled: command substitution,
			     shell functions, and  subshells  invoked  with  (
			     command ) inherit the ERR trap.
	      extglob If set, the extended pattern matching features described
		      above under Pathname Expansion are enabled.
	      extquote
		      If set, $'string'	and  $"string"	quoting	 is  performed
		      within   ${parameter}   expansions  enclosed  in	double
		      quotes.  This option is enabled by default.
	      failglob
		      If set, patterns which fail to  match  filenames	during
		      pathname expansion result	in an expansion	error.
	      force_fignore
		      If  set,	the  suffixes  specified  by the FIGNORE shell
		      variable cause words to be ignored when performing  word
		      completion even if the ignored words are the only	possi-
		      ble  completions.	  See  SHELL  VARIABLES	 above	for  a
		      description  of  FIGNORE.	  This	option	is  enabled by
		      default.
	      globasciiranges
		      If set,  range  expressions  used	 in  pattern  matching
		      bracket  expressions (see	Pattern	Matching above)	behave
		      as if in the traditional C locale	when  performing  com-
		      parisons.	  That	is,  the  current  locale's  collating
		      sequence is not taken into account, so b will  not  col-
		      late  between  A	and  B,	 and upper-case	and lower-case
		      ASCII characters will collate together.
	      globstar
		      If set, the pattern ** used in a pathname	expansion con-
		      text  will  match	all files and zero or more directories
		      and subdirectories.  If the pattern is followed by a  /,
		      only directories and subdirectories match.
	      gnu_errfmt
		      If set, shell error messages are written in the standard
		      GNU error	message	format.
	      histappend
		      If set, the history list is appended to the  file	 named
		      by  the  value  of  the HISTFILE variable	when the shell
		      exits, rather than overwriting the file.
	      histreedit
		      If set, and readline is being used, a user is given  the
		      opportunity to re-edit a failed history substitution.
	      histverify
		      If  set, and readline is being used, the results of his-
		      tory substitution	are  not  immediately  passed  to  the
		      shell  parser.   Instead,	 the  resulting	line is	loaded
		      into the readline	editing	buffer,	allowing further modi-
		      fication.
	      hostcomplete
		      If set, and readline is being used, bash will attempt to
		      perform hostname completion when a word containing  a  @
		      is   being  completed  (see  Completing  under  READLINE
		      above).  This is enabled by default.
	      huponexit
		      If set, bash will	send SIGHUP to all jobs	when an	inter-
		      active login shell exits.
	      inherit_errexit
		      If  set,	command	substitution inherits the value	of the
		      errexit option, instead of unsetting it in the  subshell
		      environment.   This option is enabled when posix mode is
		      enabled.
	      interactive_comments
		      If set, allow a word beginning with # to cause that word
		      and  all remaining characters on that line to be ignored
		      in an interactive	 shell	(see  COMMENTS	above).	  This
		      option is	enabled	by default.
	      lastpipe
		      If  set,	and  job control is not	active,	the shell runs
		      the last command of a pipeline not executed in the back-
		      ground in	the current shell environment.
	      lithist If  set,	and  the cmdhist option	is enabled, multi-line
		      commands are saved to the	history	with embedded newlines
		      rather than using	semicolon separators where possible.
	      login_shell
		      The  shell  sets this option if it is started as a login
		      shell (see INVOCATION above).   The  value  may  not  be
		      changed.
	      mailwarn
		      If  set,	and  a file that bash is checking for mail has
		      been accessed since the last time	it  was	 checked,  the
		      message  ``The  mail in mailfile has been	read'' is dis-
		      played.
	      no_empty_cmd_completion
		      If set, and  readline  is	 being	used,  bash  will  not
		      attempt to search	the PATH for possible completions when
		      completion is attempted on an empty line.
	      nocaseglob
		      If set, bash matches  filenames  in  a  case-insensitive
		      fashion when performing pathname expansion (see Pathname
		      Expansion	above).
	      nocasematch
		      If set, bash  matches  patterns  in  a  case-insensitive
		      fashion when performing matching while executing case or
		      [[ conditional commands, when performing pattern substi-
		      tution  word expansions, or when filtering possible com-
		      pletions as part of programmable completion.
	      nullglob
		      If set, bash allows patterns which match no  files  (see
		      Pathname	Expansion  above)  to expand to	a null string,
		      rather than themselves.
	      progcomp
		      If set, the programmable completion facilities (see Pro-
		      grammable	Completion above) are enabled.	This option is
		      enabled by default.
	      promptvars
		      If set, prompt strings undergo parameter expansion, com-
		      mand   substitution,  arithmetic	expansion,  and	 quote
		      removal after being expanded as described	 in  PROMPTING
		      above.  This option is enabled by	default.
	      restricted_shell
		      The   shell  sets	 this  option  if  it  is  started  in
		      restricted mode (see RESTRICTED SHELL below).  The value
		      may  not be changed.  This is not	reset when the startup
		      files are	executed, allowing the startup files  to  dis-
		      cover whether or not a shell is restricted.
	      shift_verbose
		      If  set,	the shift builtin prints an error message when
		      the shift	count exceeds the number of positional parame-
		      ters.
	      sourcepath
		      If set, the source (.) builtin uses the value of PATH to
		      find the directory containing the	file  supplied	as  an
		      argument.	 This option is	enabled	by default.
	      xpg_echo
		      If   set,	 the  echo  builtin  expands  backslash-escape
		      sequences	by default.

       suspend [-f]
	      Suspend the execution of this shell until	it receives a  SIGCONT
	      signal.  A login shell cannot be suspended; the -f option	can be
	      used to override this and	force the suspension.  The return sta-
	      tus  is  0  unless the shell is a	login shell and	-f is not sup-
	      plied, or	if job control is not enabled.

       test expr
       [ expr ]
	      Return a status of 0 (true) or 1 (false) depending on the	evalu-
	      ation of the conditional expression expr.	 Each operator and op-
	      erand must be a separate argument.  Expressions are composed  of
	      the  primaries  described	 above	under CONDITIONAL EXPRESSIONS.
	      test does	not accept any options,	nor does it accept and	ignore
	      an argument of --	as signifying the end of options.

	      Expressions  may	be  combined  using  the  following operators,
	      listed  in  decreasing  order  of	 precedence.   The  evaluation
	      depends  on the number of	arguments; see below.  Operator	prece-
	      dence is used when there are five	or more	arguments.
	      !	expr True if expr is false.
	      (	expr )
		     Returns the value of expr.	 This may be used to  override
		     the normal	precedence of operators.
	      expr1 -a expr2
		     True if both expr1	and expr2 are true.
	      expr1 -o expr2
		     True if either expr1 or expr2 is true.

	      test and [ evaluate conditional expressions using	a set of rules
	      based on the number of arguments.

	      0	arguments
		     The expression is false.
	      1	argument
		     The expression is true if and only	if the argument	is not
		     null.
	      2	arguments
		     If	the first argument is !, the expression	is true	if and
		     only if the second	argument is null.  If the first	 argu-
		     ment  is  one  of	the unary conditional operators	listed
		     above under CONDITIONAL EXPRESSIONS,  the	expression  is
		     true if the unary test is true.  If the first argument is
		     not a valid unary conditional operator, the expression is
		     false.
	      3	arguments
		     The following conditions are applied in the order listed.
		     If	the second argument is one of the  binary  conditional
		     operators listed above under CONDITIONAL EXPRESSIONS, the
		     result of the expression is the result of the binary test
		     using  the	first and third	arguments as operands.	The -a
		     and -o operators are  considered  binary  operators  when
		     there  are	 three arguments.  If the first	argument is !,
		     the value is the negation of the two-argument test	 using
		     the second	and third arguments.  If the first argument is
		     exactly ( and the third argument is exactly ), the	result
		     is	 the one-argument test of the second argument.	Other-
		     wise, the expression is false.
	      4	arguments
		     If	the first argument is !, the result is the negation of
		     the  three-argument  expression composed of the remaining
		     arguments.	 Otherwise, the	expression is parsed and eval-
		     uated  according  to  precedence  using  the rules	listed
		     above.
	      5	or more	arguments
		     The expression  is	 parsed	 and  evaluated	 according  to
		     precedence	using the rules	listed above.

	      When  used  with	test  or [, the	< and >	operators sort lexico-
	      graphically using	ASCII ordering.

       times  Print the	accumulated user and system times for  the  shell  and
	      for processes run	from the shell.	 The return status is 0.

       trap [-lp] [[arg] sigspec ...]
	      The  command  arg	 is  to	 be  read  and executed	when the shell
	      receives signal(s) sigspec.  If arg is absent (and  there	 is  a
	      single  sigspec)	or  -,	each  specified	signal is reset	to its
	      original disposition (the	value it  had  upon  entrance  to  the
	      shell).	If arg is the null string the signal specified by each
	      sigspec is ignored by the	shell and by the commands it  invokes.
	      If  arg  is  not present and -p has been supplied, then the trap
	      commands associated with each  sigspec  are  displayed.	If  no
	      arguments	 are  supplied or if only -p is	given, trap prints the
	      list of commands associated with each  signal.   The  -l	option
	      causes  the shell	to print a list	of signal names	and their cor-
	      responding numbers.   Each  sigspec  is  either  a  signal  name
	      defined  in  <signal.h>,	or  a signal number.  Signal names are
	      case insensitive and the SIG prefix is optional.

	      If a sigspec is EXIT (0) the command arg	is  executed  on  exit
	      from  the	shell.	If a sigspec is	DEBUG, the command arg is exe-
	      cuted before every simple	command, for  command,	case  command,
	      select  command,	every  arithmetic  for command,	and before the
	      first command executes in	a shell	function  (see	SHELL  GRAMMAR
	      above).	Refer to the description of the	extdebug option	to the
	      shopt builtin for	details	of its effect on the DEBUG trap.  If a
	      sigspec is RETURN, the command arg is executed each time a shell
	      function or a script executed with the . or source builtins fin-
	      ishes executing.

	      If  a  sigspec  is  ERR,	the command arg	is executed whenever a
	      pipeline (which may consist of a single simple command), a list,
	      or a compound command returns a non-zero exit status, subject to
	      the following conditions.	 The ERR trap is not executed  if  the
	      failed command is	part of	the command list immediately following
	      a	while or until keyword,	part of	the test in an	if  statement,
	      part of a	command	executed in a && or || list except the command
	      following	the final && or	||, any	command	in a pipeline but  the
	      last,  or	 if the	command's return value is being	inverted using
	      !.  These	are the	same conditions	obeyed	by  the	 errexit  (-e)
	      option.

	      Signals  ignored	upon  entry  to	the shell cannot be trapped or
	      reset.  Trapped signals that are not being ignored are reset  to
	      their original values in a subshell or subshell environment when
	      one is created.  The return status is false if  any  sigspec  is
	      invalid; otherwise trap returns true.

       type [-aftpP] name [name	...]
	      With  no options,	indicate how each name would be	interpreted if
	      used as a	command	name.  If the -t option	is used, type prints a
	      string  which  is	 one  of alias,	keyword, function, builtin, or
	      file if  name  is	 an  alias,  shell  reserved  word,  function,
	      builtin,	or disk	file, respectively.  If	the name is not	found,
	      then nothing  is	printed,  and  an  exit	 status	 of  false  is
	      returned.	  If  the  -p  option is used, type either returns the
	      name of the disk file that would be executed if name were	speci-
	      fied as a	command	name, or nothing if ``type -t name'' would not
	      return file.  The	-P option forces a PATH	search for each	 name,
	      even if ``type -t	name'' would not return	file.  If a command is
	      hashed, -p and -P	print the hashed value,	which is not necessar-
	      ily  the	file  that appears first in PATH.  If the -a option is
	      used, type prints	all of the places that contain	an  executable
	      named name.  This	includes aliases and functions,	if and only if
	      the -p option is not also	used.  The table of hashed commands is
	      not  consulted  when  using  -a.	The -f option suppresses shell
	      function lookup, as with the command builtin.  type returns true
	      if all of	the arguments are found, false if any are not found.

       ulimit [-HSabcdefiklmnpqrstuvxPT	[limit]]
	      Provides	control	 over the resources available to the shell and
	      to processes started by it, on systems that allow	such  control.
	      The -H and -S options specify that the hard or soft limit	is set
	      for the given resource.  A hard limit cannot be increased	 by  a
	      non-root	user  once it is set; a	soft limit may be increased up
	      to the value of the hard limit.  If neither -H nor -S is	speci-
	      fied, both the soft and hard limits are set.  The	value of limit
	      can be a number in the unit specified for	the resource or	one of
	      the special values hard, soft, or	unlimited, which stand for the
	      current hard limit,  the	current	 soft  limit,  and  no	limit,
	      respectively.   If  limit	 is  omitted, the current value	of the
	      soft limit of the	resource is printed, unless the	-H  option  is
	      given.  When more	than one resource is specified,	the limit name
	      and unit are printed before the value.  Other options are	inter-
	      preted as	follows:
	      -a     All current limits	are reported
	      -b     The maximum socket	buffer size
	      -c     The maximum size of core files created
	      -d     The maximum size of a process's data segment
	      -e     The maximum scheduling priority ("nice")
	      -f     The  maximum  size	 of files written by the shell and its
		     children
	      -i     The maximum number	of pending signals
	      -k     The maximum number	of kqueues that	may be allocated
	      -l     The maximum size that may be locked into memory
	      -m     The maximum resident set size (many systems do not	 honor
		     this limit)
	      -n     The maximum number	of open	file descriptors (most systems
		     do	not allow this value to	be set)
	      -p     The pipe size in 512-byte blocks (this may	not be set)
	      -q     The maximum number	of bytes in POSIX message queues
	      -r     The maximum real-time scheduling priority
	      -s     The maximum stack size
	      -t     The maximum amount	of cpu time in seconds
	      -u     The maximum number	of processes  available	 to  a	single
		     user
	      -v     The  maximum  amount  of  virtual memory available	to the
		     shell and,	on some	systems, to its	children
	      -x     The maximum number	of file	locks
	      -P     The maximum number	of pseudoterminals
	      -T     The maximum number	of threads

	      If limit is given, and the -a option is not used,	limit  is  the
	      new  value  of  the  specified resource.	If no option is	given,
	      then -f is assumed.  Values are in 1024-byte increments,	except
	      for  -t,	which is in seconds; -p, which is in units of 512-byte
	      blocks; -P, -T, -b, -k, -n, and -u, which	are  unscaled  values;
	      and, when	in Posix mode, -c and -f, which	are in 512-byte	incre-
	      ments.  The return status	is 0 unless an invalid option or argu-
	      ment  is supplied, or an error occurs while setting a new	limit.

       umask [-p] [-S] [mode]
	      The user file-creation mask is set to mode.  If mode begins with
	      a	 digit,	 it is interpreted as an octal number; otherwise it is
	      interpreted as a symbolic	mode mask similar to that accepted  by
	      chmod(1).	  If mode is omitted, the current value	of the mask is
	      printed.	The -S option causes the mask to be  printed  in  sym-
	      bolic  form;  the	 default output	is an octal number.  If	the -p
	      option is	supplied, and mode is omitted, the output is in	a form
	      that may be reused as input.  The	return status is 0 if the mode
	      was successfully changed or if no	mode  argument	was  supplied,
	      and false	otherwise.

       unalias [-a] [name ...]
	      Remove  each  name  from	the list of defined aliases.  If -a is
	      supplied,	all alias definitions are removed.  The	 return	 value
	      is true unless a supplied	name is	not a defined alias.

       unset [-fv] [-n]	[name ...]
	      For  each	 name,	remove the corresponding variable or function.
	      If the -v	option is given, each name refers to a shell variable,
	      and  that	 variable  is removed.	Read-only variables may	not be
	      unset.  If -f is specified, each name refers to  a  shell	 func-
	      tion,  and the function definition is removed.  If the -n	option
	      is supplied, and name is a variable with the nameref  attribute,
	      name  will  be unset rather than the variable it references.  -n
	      has no effect if the -f option is	supplied.  If no  options  are
	      supplied,	 each  name refers to a	variable; if there is no vari-
	      able by that name, any function with that	name is	 unset.	  Each
	      unset  variable  or  function  is	 removed  from the environment
	      passed to	subsequent commands.  If any of	COMP_WORDBREAKS,  RAN-
	      DOM, SECONDS, LINENO, HISTCMD, FUNCNAME, GROUPS, or DIRSTACK are
	      unset, they lose their special properties, even if they are sub-
	      sequently	reset.	The exit status	is true	unless a name is read-
	      only.

       wait [-n] [n ...]
	      Wait for each specified child process and	return its termination
	      status.  Each n may be a process ID or a job specification; if a
	      job spec is given, all processes	in  that  job's	 pipeline  are
	      waited  for.  If n is not	given, all currently active child pro-
	      cesses are waited	for, and the return status is zero.  If	the -n
	      option  is  supplied,  wait  waits  for any job to terminate and
	      returns its exit status.	If n specifies a non-existent  process
	      or  job, the return status is 127.  Otherwise, the return	status
	      is the exit status of the	last process or	job waited for.

RESTRICTED SHELL
       If bash is started with the name	rbash, or the -r option	is supplied at
       invocation,  the	 shell becomes restricted.  A restricted shell is used
       to set up an environment	more controlled	than the standard  shell.   It
       behaves	identically  to	bash with the exception	that the following are
       disallowed or not performed:

       o      changing directories with	cd

       o      setting or unsetting the values of SHELL,	PATH, ENV, or BASH_ENV

       o      specifying command names containing /

       o      specifying  a  filename  containing  a / as an argument to the .
	      builtin command

       o      specifying a filename containing a slash as an argument  to  the
	      -p option	to the hash builtin command

       o      importing	 function  definitions	from  the shell	environment at
	      startup

       o      parsing the value	of SHELLOPTS from  the	shell  environment  at
	      startup

       o      redirecting output using the >, >|, <>, >&, &>, and >> redirect-
	      ion operators

       o      using the	exec builtin command to	replace	the shell with another
	      command

       o      adding  or  deleting builtin commands with the -f	and -d options
	      to the enable builtin command

       o      using the	 enable	 builtin  command  to  enable  disabled	 shell
	      builtins

       o      specifying the -p	option to the command builtin command

       o      turning off restricted mode with set +r or set +o	restricted.

       These restrictions are enforced after any startup files are read.

       When a command that is found to be a shell script is executed (see COM-
       MAND EXECUTION above), rbash turns off any restrictions	in  the	 shell
       spawned to execute the script.

SEE ALSO
       Bash Reference Manual, Brian Fox	and Chet Ramey
       The Gnu Readline	Library, Brian Fox and Chet Ramey
       The Gnu History Library,	Brian Fox and Chet Ramey
       Portable	 Operating  System  Interface (POSIX) Part 2: Shell and	Utili-
       ties, IEEE --
	      http://pubs.opengroup.org/onlinepubs/9699919799/
       http://tiswww.case.edu/~chet/bash/POSIX -- a description	of posix mode
       sh(1), ksh(1), csh(1)
       emacs(1), vi(1)
       readline(3)

FILES
       /usr/local/bin/bash
	      The bash executable
       /etc/profile
	      The systemwide initialization file, executed for login shells
       ~/.bash_profile
	      The personal initialization file,	executed for login shells
       ~/.bashrc
	      The individual per-interactive-shell startup file
       ~/.bash_logout
	      The  individual  login shell cleanup file, executed when a login
	      shell exits
       ~/.inputrc
	      Individual readline initialization file

AUTHORS
       Brian Fox, Free Software	Foundation
       bfox@gnu.org

       Chet Ramey, Case	Western	Reserve	University
       chet.ramey@case.edu

BUG REPORTS
       If you find a bug in bash, you should report it.	 But first, you	should
       make  sure  that	 it really is a	bug, and that it appears in the	latest
       version	of  bash.   The	 latest	 version  is  always  available	  from
       ftp://ftp.gnu.org/pub/gnu/bash/.

       Once  you  have	determined that	a bug actually exists, use the bashbug
       command to submit a bug report.	If you have a fix, you are  encouraged
       to  mail	that as	well!  Suggestions and `philosophical' bug reports may
       be mailed  to  bug-bash@gnu.org	or  posted  to	the  Usenet  newsgroup
       gnu.bash.bug.

       ALL bug reports should include:

       The version number of bash
       The hardware and	operating system
       The compiler used to compile
       A description of	the bug	behaviour
       A short script or `recipe' which	exercises the bug

       bashbug	inserts	 the first three items automatically into the template
       it provides for filing a	bug report.

       Comments	and bug	reports	concerning this	manual page should be directed
       to chet.ramey@case.edu.

BUGS
       It's too	big and	too slow.

       There are some subtle differences between bash and traditional versions
       of sh, mostly because of	the POSIX specification.

       Aliases are confusing in	some uses.

       Shell builtin commands and functions are	not stoppable/restartable.

       Compound	commands and command sequences of the form `a ;	b ; c' are not
       handled	gracefully  when  process  suspension  is  attempted.	When a
       process is stopped, the shell immediately executes the next command  in
       the  sequence.	It  suffices to	place the sequence of commands between
       parentheses to force it into a subshell,	which  may  be	stopped	 as  a
       unit.

       Array variables may not (yet) be	exported.

       There may be only one active coprocess at a time.

GNU Bash 4.4			2016 August 26			       BASH(1)

NAME | SYNOPSIS | COPYRIGHT | DESCRIPTION | OPTIONS | ARGUMENTS | INVOCATION | DEFINITIONS | RESERVED WORDS | SHELL GRAMMAR | COMMENTS | QUOTING | PARAMETERS | EXPANSION | REDIRECTION | ALIASES | FUNCTIONS | ARITHMETIC EVALUATION | CONDITIONAL EXPRESSIONS | SIMPLE COMMAND EXPANSION | COMMAND EXECUTION | COMMAND EXECUTION ENVIRONMENT | ENVIRONMENT | EXIT STATUS | SIGNALS | JOB CONTROL | PROMPTING | READLINE | HISTORY | HISTORY EXPANSION | SHELL BUILTIN COMMANDS | RESTRICTED SHELL | SEE ALSO | FILES | AUTHORS | BUG REPORTS | BUGS

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