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KSH(1)				 User commands				KSH(1)

       ksh - Public domain Korn	shell

       ksh [+-abCefhikmnprsuvxX] [+-o option] [	[ -c command-string [command-
       name] | -s | file ] [argument ...] ]

       ksh is a	command	interpreter that is intended for both interactive  and
       shell  script  use.   Its  command  language is a superset of the sh(1)
       shell language.

   Shell Startup
       The following options can be specified only on the command line:

       -c command-string
	      the shell	executes the command(s)	contained in command-string

       -i     interactive mode -- see below

       -l     login shell -- see below interactive mode	-- see below

       -s     the shell	reads commands from standard input; all	non-option ar-
	      guments are positional parameters

       -r     restricted mode -- see below

       In  addition  to	 the  above, the options described in the set built-in
       command can also	be used	on the command line.

       If neither the -c nor the -s options are	specified, the	first  non-op-
       tion  argument  specifies  the  name of a file the shell	reads commands
       from; if	there are no non-option	arguments, the	shell  reads  commands
       from  standard input.  The name of the shell (i.e., the contents	of the
       $0) parameter is	determined as follows: if the -c option	 is  used  and
       there is	a non-option argument, it is used as the name; if commands are
       being read from a file, the file	is used	as  the	 name;	otherwise  the
       name the	shell was called with (i.e., argv[0]) is used.

       A shell is interactive if the -i	option is used or if both standard in-
       put and standard	error are attached to a	tty.  An interactive shell has
       job control enabled (if available), ignores the INT, QUIT and TERM sig-
       nals, and prints	prompts	before reading input (see PS1 and PS2  parame-
       ters).	For  non-interactive  shells, the trackall option is on	by de-
       fault (see set command below).

       A shell is restricted if	the -r option is used or if either  the	 base-
       name of the name	the shell is invoked with or the SHELL parameter match
       the pattern *r*sh (e.g.,	rsh, rksh, rpdksh, etc.).  The	following  re-
       strictions  come	 into effect after the shell processes any profile and
       $ENV files:
	 o    the cd command is	disabled
	 o    the SHELL, ENV and PATH parameters can't be changed
	 o    command names can't be specified with absolute or	relative paths
	 o    the -p option of the command built-in can't be used
	 o    redirections that	create files can't be used (i.e., >,  >|,  >>,

       A  shell	 is privileged if the -p option	is used	or if the real user-id
       or group-id does	not match the effective	user-id	or group-id  (see  ge-
       tuid(2),	 getgid(2)).   A privileged shell does not process $HOME/.pro-
       file nor	the ENV	parameter (see below), instead the file	/etc/suid_pro-
       file  is	processed.  Clearing the privileged option causes the shell to
       set its effective user-id (group-id) to its real	user-id	(group-id).

       If the basename of the name the shell is	called	with  (i.e.,  argv[0])
       starts with - or	if the -l option is used, the shell is assumed to be a
       login shell and the shell reads and executes the	contents of  /etc/pro-
       file, $HOME/.profile and	$ENV if	they exist and are readable.

       If  the	ENV parameter is set when the shell starts (or,	in the case of
       login shells, after any profiles	are processed),	its value is subjected
       to  parameter,  command,	 arithmetic and	tilde substitution and the re-
       sulting file (if	any) is	read and executed.  If the  ENV	 parameter  is
       not  set	 (and  not  null) the file $HOME/.kshrc	is included (after the
       above mentioned substitutions have been performed).

       The exit	status of the shell is 127 if the command  file	 specified  on
       the command line	could not be opened, or	non-zero if a fatal syntax er-
       ror occurred during the execution of a script.  In the absence of fatal
       errors,	the exit status	is that	of the last command executed, or zero,
       if no command is	executed.

   Command Syntax
       The shell begins	parsing	its input by breaking it into  words.	Words,
       which  are  sequences  of  characters, are delimited by unquoted	white-
       space characters	(space,	tab and	newline) or meta-characters (<,	>,  |,
       ;,  &,  ( and )).  Aside	from delimiting	words, spaces and tabs are ig-
       nored, while newlines usually delimit  commands.	  The  meta-characters
       are  used  in building the following tokens: <, <&, <<, >, >&, >>, etc.
       are used	to specify redirections	(see Input/Output Redirection  below);
       |  is  used to create pipelines;	|& is used to create co-processes (see
       Co-Processes below); ; is used to separate commands; & is used to  cre-
       ate  asynchronous  pipelines; &&	and || are used	to specify conditional
       execution; ;; is	used in	case statements; (( .. )) are used  in	arith-
       metic expressions; and lastly, (	.. ) are used to create	subshells.

       White-space  and	meta-characters	can be quoted individually using back-
       slash (\), or in	groups using double (")	or single  (')	quotes.	  Note
       that  the  following characters are also	treated	specially by the shell
       and must	be quoted if they are to represent themselves: \, ", ',	#,  $,
       `,  ~,  {,  }, *, ? and [.  The first three of these are	the above men-
       tioned quoting characters (see Quoting below); #, if used at the	begin-
       ning  of	 a  word, introduces a comment -- everything after the # up to
       the nearest newline is ignored; $ is used to introduce parameter,  com-
       mand  and  arithmetic  substitutions (see Substitution below); `	intro-
       duces an	old-style command substitution (see Substitution below); ~ be-
       gins a directory	expansion (see Tilde Expansion below); { and } delimit
       csh(1) style alternations (see Brace Expansion below); and, finally, *,
       ?  and  [  are used in file name	generation (see	File Name Patterns be-

       As words	and tokens are parsed, the shell  builds  commands,  of	 which
       there are two basic types: simple-commands, typically programs that are
       executed, and compound-commands,	such as	for and	if statements,	group-
       ing constructs and function definitions.

       A  simple-command consists of some combination of parameter assignments
       (see Parameters below),	input/output  redirections  (see  Input/Output
       Redirections  below),  and  command words; the only restriction is that
       parameter assignments come  before  any	command	 words.	  The  command
       words,  if any, define the command that is to be	executed and its argu-
       ments.  The command may be a shell built-in command, a function	or  an
       external	 command, i.e.,	a separate executable file that	is located us-
       ing the PATH parameter (see Command Execution below).   Note  that  all
       command	constructs have	an exit	status:	for external commands, this is
       related to the status returned by wait(2) (if the command could not  be
       found,  the  exit  status is 127, if it could not be executed, the exit
       status is 126); the exit	status of other	command	 constructs  (built-in
       commands, functions, compound-commands, pipelines, lists, etc.) are all
       well defined and	are described where the	construct is  described.   The
       exit  status  of	 a command consisting only of parameter	assignments is
       that of the last	command	substitution performed	during	the  parameter
       assignment or zero if there were	no command substitutions.

       Commands	 can  be chained together using	the | token to form pipelines,
       in which	the standard output of each command but	the last is piped (see
       pipe(2))	to the standard	input of the following command.	 The exit sta-
       tus of a	pipeline is that of its	last command.  A pipeline may be  pre-
       fixed  by the ! reserved	word which causes the exit status of the pipe-
       line to be logically complemented: if the original  status  was	0  the
       complemented  status  will  be 1, and if	the original status was	not 0,
       then the	complemented status will be 0.

       Lists of	commands can be	created	by separating pipelines	by any of  the
       following  tokens:  &&,	||, &, |& and ;.  The first two	are for	condi-
       tional execution: cmd1 && cmd2 executes cmd2 only if the	exit status of
       cmd1  is	 zero; || is the opposite -- cmd2 is executed only if the exit
       status of cmd1 is non-zero.  && and || have equal precedence  which  is
       higher than that	of &, |& and ;,	which also have	equal precedence.  The
       & token causes the preceding command  to	 be  executed  asynchronously,
       that is,	the shell starts the command, but does not wait	for it to com-
       plete (the shell	does keep track	of the status of asynchronous commands
       --  see	Job  Control  below).  When an asynchronous command is started
       when job	control	is disabled (i.e., in most scripts),  the  command  is
       started	with  signals  INT  and	QUIT ignored and with input redirected
       from /dev/null (however,	redirections  specified	 in  the  asynchronous
       command have precedence).  The |& operator starts a co-process which is
       special kind of asynchronous process (see  Co-Processes	below).	  Note
       that  a	command	 must  follow the && and || operators, while a command
       need not	follow &, |& and ;.  The exit status of	a list is that of  the
       last  command  executed,	 with the exception of asynchronous lists, for
       which the exit status is	0.

       Compound	commands are created using the	following  reserved  words  --
       these  words  are  only recognized if they are unquoted and if they are
       used as the first word of a command (i.e., they can't  be  preceded  by
       parameter assignments or	redirections):

			 case	else   function	  then	  !
			 do	esac   if	  time	  [[
			 done	fi     in	  until	  {
			 elif	for    select	  while	  }
       Note: Some shells (but not this one) execute control structure commands
       in a subshell when one or more of  their	 file  descriptors  are	 redi-
       rected,	so any environment changes inside them may fail.  To be	porta-
       ble, the	exec statement should be used instead  to  redirect  file  de-
       scriptors before	the control structure.

       In  the following compound command descriptions,	command	lists (denoted
       as list)	that are followed by reserved words  must  end	with  a	 semi-
       colon, a	newline	or a (syntactically correct) reserved word.  For exam-
	      {	echo foo; echo bar; }
	      {	echo foo; echo bar<newline>}
	      {	{ echo foo; echo bar; }	}
       are all valid, but
	      {	echo foo; echo bar }
       is not.

       ( list )
	      Execute list in a	subshell.  There is no implicit	 way  to  pass
	      environment changes from a subshell back to its parent.

       { list }
	      Compound	construct;  list  is  executed,	but not	in a subshell.
	      Note that	{ and }	are reserved words, not	meta-characters.

       case word in [ [(] pattern [| pattern] ... ) list ;; ] ... esac
	      The case statement attempts to match word	against	the  specified
	      patterns;	 the  list  associated	with  the  first  successfully
	      matched pattern is executed.  Patterns used in  case  statements
	      are  the	same  as those used for	file name patterns except that
	      the restrictions regarding . and / are dropped.  Note  that  any
	      unquoted space before and	after a	pattern	is stripped; any space
	      with a pattern must be quoted.  Both the word and	 the  patterns
	      are  subject  to parameter, command, and arithmetic substitution
	      as well as tilde substitution.  For historical reasons, open and
	      close braces may be used instead of in and esac (e.g., case $foo
	      {	*) echo	bar; }).  The exit status of a case statement is  that
	      of the executed list; if no list is executed, the	exit status is

       for name	[ in word ... term ] do	list done
	      where term is either a newline or	a ;.  For  each	 word  in  the
	      specified	 word  list, the parameter name	is set to the word and
	      list is executed.	 If in is not used to specify a	word list, the
	      positional  parameters ("$1", "$2", etc.)	are used instead.  For
	      historical reasons, open and close braces	may be used instead of
	      do  and  done (e.g., for i; { echo $i; }).  The exit status of a
	      for statement is the last	exit status of list; if	list is	 never
	      executed,	the exit status	is zero.

       if list then list [elif list then list] ... [else list] fi
	      If the exit status of the	first list is zero, the	second list is
	      executed;	otherwise the list following the elif, if any, is exe-
	      cuted with similar consequences.	If all the lists following the
	      if and elifs fail	(i.e., exit with non-zero  status),  the  list
	      following	the else is executed.  The exit	status of an if	state-
	      ment is that of non-conditional list that	 is  executed;	if  no
	      non-conditional list is executed,	the exit status	is zero.

       select name [ in	word ... term ]	do list	done
	      where  term  is  either  a newline or a ;.  The select statement
	      provides an automatic method of presenting the user with a  menu
	      and  selecting  from  it.	  An  enumerated list of the specified
	      words is printed on standard error, followed by a	 prompt	 (PS3,
	      normally	`#?  ').  A number corresponding to one	of the enumer-
	      ated words is then read from standard input, name	is set to  the
	      selected word (or	is unset if the	selection is not valid), REPLY
	      is set to	what was read (leading/trailing	 space	is  stripped),
	      and  list	 is executed.  If a blank line (i.e., zero or more IFS
	      characters) is entered, the menu is re-printed without executing
	      list.   When  list  completes, the enumerated list is printed if
	      REPLY is null, the prompt	is printed and so on.  This process is
	      continues	until an end-of-file is	read, an interrupt is received
	      or a break statement is executed inside the loop.	  If  in  word
	      ...  is omitted, the positional parameters are used (i.e., "$1",
	      "$2", etc.).  For	historical reasons, open and close braces  may
	      be  used	instead	of do and done (e.g., select i;	{ echo $i; }).
	      The exit status of a select statement is zero if a break	state-
	      ment is used to exit the loop, non-zero otherwise.

       until list do list done
	      This  works  like	 while,	 except	that the body is executed only
	      while the	exit status of the first list is non-zero.

       while list do list done
	      A	while is a prechecked loop.  Its body is executed as often  as
	      the exit status of the first list	is zero.  The exit status of a
	      while statement is the last exit status of the list in the  body
	      of  the  loop;  if  the body is not executed, the	exit status is

       function	name { list }
	      Defines the function name.   See	Functions  below.   Note  that
	      redirections specified after a function definition are performed
	      whenever the function is executed, not when the function defini-
	      tion is executed.

       name () command
	      Mostly the same as function.  See	Functions below.

       time [ -p ] [ pipeline ]
	      The  time	 reserved  word	 is described in the Command Execution

       (( expression ))
	      The arithmetic expression	expression is evaluated; equivalent to
	      let  "expression".   See Arithmetic Expressions and the let com-
	      mand below.

       [[ expression ]]
	      Similar to the test and [	... ] commands (described later), with
	      the following exceptions:
		o    Field  splitting  and  file  name generation are not per-
		     formed on arguments.
		o    The -a (and) and -o (or) operators	are replaced  with  &&
		     and ||, respectively.
		o    Operators (e.g., -f, =, !,	etc.) must be unquoted.
		o    The  second  operand of !=	and = expressions are patterns
		     (e.g., the	comparison in
					[[ foobar = f*r	]]
		o    There are two additional binary operators:	< and >	 which
		     return  true  if their first string operand is less than,
		     or	greater	than, their  second  string  operand,  respec-
		o    The  single argument form of test,	which tests if the ar-
		     gument has	non-zero length, is not	valid -	explicit oper-
		     ators must	always be used,	e.g., instead of
					      [	str ]
					   [[ -n str ]]
		o    Parameter,	 command and arithmetic	substitutions are per-
		     formed as expressions are evaluated and  lazy  expression
		     evaluation	 is  used  for	the && and || operators.  This
		     means that	in the statement
				  [[ -r	foo && $(< foo)	= b*r ]]
		     the $(< foo) is evaluated if and only if the file foo ex-
		     ists and is readable.

       Quoting	is used	to prevent the shell from treating characters or words
       specially.  There are three methods of quoting:	First,	\  quotes  the
       following  character,  unless it	is at the end of a line, in which case
       both the	\ and the newline are stripped.	 Second, a  single  quote  (')
       quotes  everything  up  to the next single quote	(this may span lines).
       Third, a	double quote (") quotes	all characters,	except $, ` and	\,  up
       to  the	next unquoted double quote.  $ and ` inside double quotes have
       their usual meaning (i.e., parameter, command or	 arithmetic  substitu-
       tion)  except  no field splitting is carried out	on the results of dou-
       ble-quoted substitutions.  If a \ inside	a double-quoted	string is fol-
       lowed by	\, $, `	or ", it is replaced by	the second character; if it is
       followed	by a newline, both the \ and the newline are stripped;	other-
       wise, both the \	and the	character following are	unchanged.

       Note:  An  earlier  version of ksh(1) changed the interpretation	of se-
       quences of the form "...`...\"...`.."   according  to  whether  or  not
       POSIX mode was in effect.  In the current implementation, the backslash
       in \" is	seen and removed by the	outer "...", so	the backslash  is  not
       seen by the inner `...`.

       There  are  two	types  of  aliases: normal command aliases and tracked
       aliases.	 Command aliases are normally used as a	short hand for a  long
       or  often  used command.	 The shell expands command aliases (i.e., sub-
       stitutes	the alias name for its value) when it reads the	first word  of
       a  command.   An	 expanded  alias  is  re-processed  to	check for more
       aliases.	 If a command alias ends in a space or tab, the	following word
       is also checked for alias expansion.  The alias expansion process stops
       when a word that	is not an alias	is found, when a quoted	word is	 found
       or when an alias	word that is currently being expanded is found.

       The following command aliases are defined automatically by the shell:
	      autoload='typeset	-fu'
	      functions='typeset -f'
	      hash='alias -t'
	      history='fc -l'
	      integer='typeset -i'
	      login='exec login'
	      nohup='nohup '
	      r='fc -e -'
	      stop='kill -STOP'
	      suspend='kill -STOP $$'
	      type='whence -v'

       Tracked aliases allow the shell to remember where it found a particular
       command.	 The first time	the shell does a path  search  for  a  command
       that  is	 marked	as a tracked alias, it saves the full path of the com-
       mand.  The next time the	command	is  executed,  the  shell  checks  the
       saved  path  to see that	it is still valid, and if so, avoids repeating
       the path	search.	 Tracked aliases can be	listed and created using alias
       -t.   Note  that	changing the PATH parameter clears the saved paths for
       all tracked aliases.  If	the trackall  option  is  set  (i.e.,  set  -o
       trackall	or set -h), the	shell tracks all commands.  This option	is set
       automatically for non-interactive shells.  For interactive shells, only
       the  following  commands	are automatically tracked: cat,	cc, chmod, cp,
       date, ed, emacs,	grep, ls, mail,	make, mv, pr, rm, sed, sh, vi and who.

       The first step the shell	takes in executing a simple-command is to per-
       form  substitutions on the words	of the command.	 There are three kinds
       of substitution:	parameter, command and arithmetic.  Parameter  substi-
       tutions,	 which	are  described in detail in the	next section, take the
       form $name or ${...}; command substitutions take	the form $(command) or
       `command`; and arithmetic substitutions take the	form $((expression)).

       If  a substitution appears outside of double quotes, the	results	of the
       substitution are	generally subject to word or field splitting according
       to the current value of the IFS parameter.  The IFS parameter specifies
       a list of characters which are used to break a string up	 into  several
       words;  any  characters from the	set space, tab and newline that	appear
       in the IFS characters are called	IFS white space.  Sequences of one  or
       more  IFS  white	space characters, in combination with zero or one non-
       IFS white space characters delimit a field.  As a special case, leading
       and  trailing IFS white space is	stripped (i.e.,	no leading or trailing
       empty field is created by it); leading or trailing non-IFS white	 space
       does  create an empty field.  Example: if IFS is	set to `<space>:', the
       sequence	of  characters	`<space>A<space>:<space><space>B::D'  contains
       four  fields:  `A', `B',	`' and `D'.  Note that if the IFS parameter is
       set to the null string, no field	splitting is done; if the parameter is
       unset, the default value	of space, tab and newline is used.

       The  results of substitution are, unless	otherwise specified, also sub-
       ject to brace expansion and file	name expansion (see the	relevant  sec-
       tions below).

       A command substitution is replaced by the output	generated by the spec-
       ified command, which is run in a	subshell.   For	 $(command)  substitu-
       tions,  normal  quoting rules are used when command is parsed, however,
       for the `command` form, a \ followed by any of $, ` or \	is stripped (a
       \  followed by any other	character is unchanged).  As a special case in
       command substitutions, a	command	of the form < file is  interpreted  to
       mean  substitute	 the contents of file ($(< foo)	has the	same effect as
       $(cat foo), but it is carried out more efficiently because  no  process
       is started).
       NOTE: $(command)	expressions are	currently parsed by finding the	match-
       ing parenthesis,	regardless of quoting.	This will hopefully  be	 fixed

       Arithmetic substitutions	are replaced by	the value of the specified ex-
       pression.  For example, the command echo	 $((2+3*4))  prints  14.   See
       Arithmetic Expressions for a description	of an expression.

       Parameters  are	shell variables; they can be assigned values and their
       values can be accessed using a  parameter  substitution.	  A  parameter
       name is either one of the special single	punctuation or digit character
       parameters described below, or a	letter followed	by zero	or  more  let-
       ters or digits (`_' counts as a letter).	 The later form	can be treated
       as arrays by appending an array index of	the form: [expr] where expr is
       an  arithmetic  expression.  Array indices are currently	limited	to the
       range 0 through 1023, inclusive.	 Parameter substitutions take the form
       $name,  ${name}	or  ${name[expr]}, where name is a parameter name.  If
       substitution is performed on a parameter	(or an	array  parameter  ele-
       ment)  that is not set, a null string is	substituted unless the nounset
       option (set -o nounset or set -u) is set, in which case	an  error  oc-

       Parameters  can	be  assigned  values  in a number of ways.  First, the
       shell implicitly	sets some parameters like #, PWD, etc.;	 this  is  the
       only  way the special single character parameters are set.  Second, pa-
       rameters	are imported from the shell's environment at startup.	Third,
       parameters  can	be  assigned  values on	the command line, for example,
       `FOO=bar' sets the parameter FOO	to bar;	multiple parameter assignments
       can  be	given  on  a single command line and they can be followed by a
       simple-command, in which	case the assignments are in  effect  only  for
       the  duration  of  the command (such assignments	are also exported, see
       below for implications of this).	 Note that both	the parameter name and
       the  =  must be unquoted	for the	shell to recognize a parameter assign-
       ment.  The fourth way of	setting	a parameter is with the	export,	 read-
       only and	typeset	commands; see their descriptions in the	Command	Execu-
       tion section.  Fifth, for and select loops set parameters  as  well  as
       the  getopts,  read and set -A commands.	 Lastly, parameters can	be as-
       signed values using assignment operators	inside arithmetic  expressions
       (see  Arithmetic	 Expressions below) or using the ${name=value} form of
       parameter substitution (see below).

       Parameters with the export attribute (set using the export  or  typeset
       -x  commands,  or by parameter assignments followed by simple commands)
       are put in the environment (see environ(7))  of	commands  run  by  the
       shell as	name=value pairs.  The order in	which parameters appear	in the
       environment of a	command	is unspecified.	 When the shell	starts up,  it
       extracts	parameters and their values from its environment and automati-
       cally sets the export attribute for those parameters.

       Modifiers can be	applied	to the ${name} form of parameter substitution:

	      if name is set and not null, it is substituted,  otherwise  word
	      is substituted.

	      if  name	is  set	 and  not null,	word is	substituted, otherwise
	      nothing is substituted.

	      if name is set and not null, it is substituted, otherwise	it  is
	      assigned word and	the resulting value of name is substituted.

	      if  name	is set and not null, it	is substituted,	otherwise word
	      is printed on standard error (preceded by	name:)	and  an	 error
	      occurs (normally causing termination of a	shell script, function
	      or .-script).  If	word is	omitted	the string `parameter null  or
	      not set' is used instead.

       In  the above modifiers,	the : can be omitted, in which case the	condi-
       tions only depend on name being set (as opposed to set and  not	null).
       If  word	 is needed, parameter, command,	arithmetic and tilde substitu-
       tion are	performed on it; if word is not	needed,	it is not evaluated.

       The following forms of parameter	substitution can also be used:

	      The number of positional parameters if name is *,	@  or  is  not
	      specified, or the	length of the string value of parameter	name.

       ${#name[*]}, ${#name[@]}
	      The number of elements in	the array name.

       ${name#pattern},	${name##pattern}
	      If pattern matches the beginning of the value of parameter name,
	      the matched text is deleted from the result of substitution.   A
	      single  #	 results in the	shortest match,	two #'s	results	in the
	      longest match.

       ${name%pattern},	${name%%pattern}
	      Like ${..#..} substitution, but it deletes from the end  of  the

       The  following  special	parameters are implicitly set by the shell and
       cannot be set directly using assignments:

       !      Process id of the	last background	process	started.  If no	 back-
	      ground processes have been started, the parameter	is not set.

       #      The number of positional parameters (i.e., $1, $2, etc.).

       $      The process ID of	the shell, or the PID of the original shell if
	      it is a subshell.

       -      The concatenation	of the current single letter options (see  set
	      command below for	list of	options).

       ?      The  exit	 status	of the last non-asynchronous command executed.
	      If the last command was killed by	a signal, $?  is  set  to  128
	      plus the signal number.

       0      The name the shell was invoked with (i.e., argv[0]), or the com-
	      mand-name	if it was invoked with the -c option and the  command-
	      name was supplied, or the	file argument, if it was supplied.  If
	      the posix	option is not set, $0 is the name of the current func-
	      tion or script.

       1 ... 9
	      The  first  nine positional parameters that were supplied	to the
	      shell, function or .-script.  Further positional parameters  may
	      be accessed using	${number}.

       *      All  positional  parameters  (except  parameter  0), i.e., $1 $2
	      $3....  If used outside of double	quotes,	parameters  are	 sepa-
	      rate  words  (which  are	subjected  to word splitting); if used
	      within double quotes, parameters	are  separated	by  the	 first
	      character	 of  the  IFS parameter	(or the	empty string if	IFS is

       @      Same as $*, unless it is used inside  double  quotes,  in	 which
	      case  a separate word is generated for each positional parameter
	      -	if there are no	positional parameters, no  word	 is  generated
	      ("$@"  can be used to access arguments, verbatim,	without	losing
	      null arguments or	splitting arguments with spaces).

       The following parameters	are set	and/or used by the shell:

       _ (underscore)
	      When an external command is executed by the shell, this  parame-
	      ter  is set in the environment of	the new	process	to the path of
	      the executed command.  In	interactive  use,  this	 parameter  is
	      also  set	 in  the parent	shell to the last word of the previous
	      command.	When MAILPATH messages are evaluated,  this  parameter
	      contains the name	of the file that changed (see MAILPATH parame-
	      ter below).

       CDPATH Search path for the cd built-in command.	Works the same way  as
	      PATH  for	those directories not beginning	with / in cd commands.
	      Note that	if CDPATH is set and does not contain .	nor  an	 empty
	      path, the	current	directory is not searched.

	      Set  to  the  number of columns on the terminal or window.  Cur-
	      rently set to the	cols value as  reported	 by  stty(1)  if  that
	      value  is	 non-zero.   This parameter is used by the interactive
	      line editing modes, and by select, set -o	and kill  -l  commands
	      to format	information in columns.

       EDITOR If  the VISUAL parameter is not set, this	parameter controls the
	      command line editing mode	for interactive	 shells.   See	VISUAL
	      parameter	below for how this works.

       ENV    If this parameter	is found to be set after any profile files are
	      executed,	the expanded value is used as a	shell  start-up	 file.
	      It typically contains function and alias definitions.

       ERRNO  Integer  value  of  the  shell's errno variable -- indicates the
	      reason the last system call failed.

	      Not implemented yet.

	      If set, this parameter is	assumed	to contain the shell  that  is
	      to  be  used to execute commands that execve(2) fails to execute
	      and which	do not start with a `#!	shell' sequence.

       FCEDIT The editor used by the fc	command	(see below).

       FPATH  Like PATH, but used when an undefined function  is  executed  to
	      locate the file defining the function.  It is also searched when
	      a	command	can't be found using PATH.  See	 Functions  below  for
	      more information.

	      The  name	 of the	file used to store history.  When assigned to,
	      history is loaded	from the specified file.  Also,	several	 invo-
	      cations of the shell running on the same machine will share his-
	      tory if their HISTFILE parameters	all point at the same file.
	      NOTE: if HISTFILE	isn't set, no history file is used.   This  is
	      different	  from	 the   original	  Korn	 shell,	  which	  uses
	      $HOME/.sh_history; in future, pdksh may also use a default  his-
	      tory file.

	      The number of commands normally stored for history, default 128.

       HOME   The  default  directory for the cd command and the value substi-
	      tuted for	an unqualified ~ (see Tilde Expansion below).

       IFS    Internal field separator,	used during substitution  and  by  the
	      read  command, to	split values into distinct arguments; normally
	      set to space, tab	and newline.  See Substitution above  for  de-
	      Note:  this  parameter is	not imported from the environment when
	      the shell	is started.

	      The version of shell and the date	the version was	created	(read-
	      only).   See also	the version commands in	Emacs Editing Mode and
	      Vi Editing Mode sections,	below.

       LINENO The line number of the function or shell	script	that  is  cur-
	      rently being executed.

       LINES  Set to the number	of lines on the	terminal or window.

	      Not implemented yet.

       MAIL   If  set, the user	will be	informed of the	arrival	of mail	in the
	      named file.  This	parameter is ignored if	the MAILPATH parameter
	      is set.

	      How  often,  in  seconds,	 the  shell will check for mail	in the
	      file(s) specified	by MAIL	or MAILPATH.  If 0, the	 shell	checks
	      before each prompt.  The default is 600 (10 minutes).

	      A	list of	files to be checked for	mail.  The list	is colon sepa-
	      rated, and each file may be followed by a	? and a	message	to  be
	      printed  if new mail has arrived.	 Command, parameter and	arith-
	      metic substitution is performed on the message, and, during sub-
	      stitution,  the parameter	$_ contains the	name of	the file.  The
	      default message is you have mail in $_.

       OLDPWD The previous working directory.  Unset if	cd  has	 not  success-
	      fully  changed  directories  since  the shell started, or	if the
	      shell doesn't know where it is.

       OPTARG When using getopts, it contains the argument for	a  parsed  op-
	      tion, if it requires one.

       OPTIND The  index  of  the  last	argument processed when	using getopts.
	      Assigning	1 to this parameter causes getopts  to	process	 argu-
	      ments from the beginning the next	time it	is invoked.

       PATH   A	 colon	separated  list	 of directories	that are searched when
	      looking for commands and .'d files.  An empty  string  resulting
	      from  a  leading	or  trailing  colon, or	two adjacent colons is
	      treated as a `.',	the current directory.

	      If set, this parameter causes the	posix option  to  be  enabled.
	      See POSIX	Mode below.

       PPID   The process ID of	the shell's parent (readonly).

       PS1    PS1  is  the  primary prompt for interactive shells.  Parameter,
	      command and arithmetic substitutions are performed, and !	is re-
	      placed  with  the	current	command	number (see fc command below).
	      A	literal	! can be put in	the prompt by placing !! in PS1.  Note
	      that  since  the command line editors try	to figure out how long
	      the prompt is (so	they know  how	far  it	 is  to	 edge  of  the
	      screen), escape codes in the prompt tend to mess things up.  You
	      can tell the shell not to	count certain sequences	(such  as  es-
	      cape codes) by prefixing your prompt with	a non-printing charac-
	      ter (such	as control-A) followed by a carriage return  and  then
	      delimiting  the  escape  codes with this non-printing character.
	      If you don't have	any non-printing  characters,  you're  out  of
	      luck...  BTW, don't blame	me for this hack; it's in the original
	      ksh.  Default is `$ ' for	non-root users,	`# ' for root.

       PS2    Secondary	prompt string, by default `> ',	used when  more	 input
	      is needed	to complete a command.

       PS3    Prompt  used  by select statement	when reading a menu selection.
	      Default is `#? '.

       PS4    Used to prefix commands that are printed during execution	 trac-
	      ing  (see	 set -x	command	below).	 Parameter, command and	arith-
	      metic substitutions are performed	before it is printed.  Default
	      is `+ '.

       PWD    The  current  working  directory.	  Maybe	unset or null if shell
	      doesn't know where it is.

       RANDOM A	simple random number generator.	 Every time RANDOM  is	refer-
	      enced, it	is assigned the	next number in a random	number series.
	      The point	in the series can be set by assigning a	number to RAN-
	      DOM (see rand(3)).

       REPLY  Default  parameter  for  the read	command	if no names are	given.
	      Also used	in select loops	to store the value that	is  read  from
	      standard input.

	      The number of seconds since the shell started or,	if the parame-
	      ter has been assigned an integer value, the  number  of  seconds
	      since the	assignment plus	the value that was assigned.

       TMOUT  If  set to a positive integer in an interactive shell, it	speci-
	      fies the maximum number of seconds the shell will	wait for input
	      after  printing  the  primary  prompt (PS1).  If the time	is ex-
	      ceeded, the shell	exits.

       TMPDIR The directory shell temporary files are created in.  If this pa-
	      rameter  is  not set, or does not	contain	the absolute path of a
	      writable directory, temporary files are created in /tmp.

       VISUAL If set, this parameter controls the command  line	 editing  mode
	      for interactive shells.  If the last component of	the path spec-
	      ified in this parameter contains the string vi, emacs or	gmacs,
	      the  vi, emacs or	gmacs (Gosling emacs) editing mode is enabled,

   Tilde Expansion
       Tilde expansion,	which is done in parallel with parameter substitution,
       is done on words	starting with an unquoted ~.  The characters following
       the tilde, up to	the first /, if	any, are assumed to be a  login	 name.
       If the login name is empty, + or	-, the value of	the HOME, PWD, or OLD-
       PWD parameter is	substituted, respectively.   Otherwise,	 the  password
       file  is	 searched for the login	name, and the tilde expression is sub-
       stituted	with the user's	home directory.	 If  the  login	 name  is  not
       found  in the password file or if any quoting or	parameter substitution
       occurs in the login name, no substitution is performed.

       In parameter assignments	(those preceding a simple-command or those oc-
       curring	in  the	 arguments  of	alias, export, readonly, and typeset),
       tilde expansion is done after any unquoted colon	(:), and  login	 names
       are also	delimited by colons.

       The  home  directory  of	previously expanded login names	are cached and
       re-used.	 The alias -d command may be used to list, change and  add  to
       this cache (e.g., `alias	-d fac=/usr/local/facilities; cd ~fac/bin').

   Brace Expansion (alternation)
       Brace expressions, which	take the form
       are  expanded to	N words, each of which is the concatenation of prefix,
       stri and	suffix (e.g., `a{c,b{X,Y},d}e'	expands	 to  four  word:  ace,
       abXe,  abYe,  and ade).	As noted in the	example, brace expressions can
       be nested and the resulting words are not  sorted.   Brace  expressions
       must contain an unquoted	comma (,) for expansion	to occur (i.e.,	{} and
       {foo} are not expanded).	 Brace expansion is carried out	after  parame-
       ter substitution	and before file	name generation.

   File	Name Patterns
       A  file	name  pattern is a word	containing one or more unquoted	? or *
       characters or [..] sequences.  Once brace expansion has been performed,
       the  shell replaces file	name patterns with the sorted names of all the
       files that match	the pattern (if	no files match,	the word is  left  un-
       changed).  The pattern elements have the	following meaning:

       ?      matches any single character.

       *      matches any sequence of characters.

       [..]   matches  any  of	the characters inside the brackets.  Ranges of
	      characters can be	specified by separating	two characters by a -,
	      e.g.,  [a0-9]  matches  the  letter a or any digit.  In order to
	      represent	itself,	a - must either	be quoted or the first or last
	      character	 in the	character list.	 Similarly, a ]	must be	quoted
	      or the first character in	the list if it is represent itself in-
	      stead of the end of the list.  Also, a !	appearing at the start
	      of the list has special meaning (see below), so to represent it-
	      self it must be quoted or	appear later in	the list.

       [!..]  like [..], except	it matches any character not inside the	brack-

       *(pattern| ... |pattern)
	      matches any string of characters that matches zero or  more  oc-
	      currences	 of  the  specified  patterns.	 Example:  the pattern
	      *(foo|bar) matches the strings `',  `foo',  `bar',  `foobarfoo',

       +(pattern| ... |pattern)
	      matches any string of characters that matches one	or more	occur-
	      rences  of  the  specified  patterns.   Example:	 the   pattern
	      +(foo|bar) matches the strings `foo', `bar', `foobarfoo',	etc..

       ?(pattern| ... |pattern)
	      matches  the  empty  string  or a	string that matches one	of the
	      specified	 patterns.   Example:  the  pattern  ?(foo|bar)	  only
	      matches the strings `', `foo' and	`bar'.

       @(pattern| ... |pattern)
	      matches  a  string  that	matches	one of the specified patterns.
	      Example: the pattern @(foo|bar) only matches the	strings	 `foo'
	      and `bar'.

       !(pattern| ... |pattern)
	      matches any string that does not match one of the	specified pat-
	      terns.  Examples:	the pattern !(foo|bar) matches all strings ex-
	      cept  `foo'  and `bar'; the pattern !(*) matches no strings; the
	      pattern !(?)* matches all	strings	(think about it).

       Note that pdksh currently never matches . and .., but the original ksh,
       Bourne sh and bash do, so this may have to change (too bad).

       Note  that none of the above pattern elements match either a period (.)
       at the start of a file name or a	slash (/), even	if they	are explicitly
       used  in	 a [..]	sequence; also,	the names . and	..  are	never matched,
       even by the pattern .*.

       If the markdirs option is set, any directories that  result  from  file
       name generation are marked with a trailing /.

       The POSIX character classes (i.e., [:class-name:] inside	a [..] expres-
       sion) are not yet implemented.

   Input/Output	Redirection
       When a command is executed, its standard	 input,	 standard  output  and
       standard	error (file descriptors	0, 1 and 2, respectively) are normally
       inherited from the shell.  Three	exceptions to  this  are  commands  in
       pipelines,  for	which  standard	input and/or standard output are those
       set up by the pipeline, asynchronous commands created when job  control
       is  disabled,  for  which  standard  input  is initially	set to be from
       /dev/null, and commands for which any  of  the  following  redirections
       have been specified:

       > file standard	output is redirected to	file.  If file does not	exist,
	      it is created; if	it does	exist, is a regular file and  the  no-
	      clobber  option  is  set,	an error occurs, otherwise the file is
	      truncated.  Note that this means the command cmd	_  foo	_  foo
	      will  open foo for reading and then truncate it when it opens it
	      for writing, before cmd gets a chance to actually	read foo.

       >| file
	      same as >, except	the file is truncated, even if	the  noclobber
	      option is	set.

       >> file
	      same  as	>, except the file an existing file is appended	to in-
	      stead of being truncated.	 Also, the file	is  opened  in	append
	      mode, so writes always go	to the end of the file (see open(2)).

       < file standard	input  is  redirected  from  file, which is opened for

       <> file
	      same as <, except	the file is opened for reading and writing.

       << marker
	      after reading the	command	line containing	this kind of redirect-
	      ion  (called  a  here document), the shell copies	lines from the
	      command source into a  temporary	file  until  a	line  matching
	      marker is	read.  When the	command	is executed, standard input is
	      redirected from the  temporary  file.   If  marker  contains  no
	      quoted  characters,  the contents	of the temporary file are pro-
	      cessed as	if enclosed in double quotes each time the command  is
	      executed,	so parameter, command and arithmetic substitutions are
	      performed, along with backslash (\) escapes  for	$,  `,	\  and
	      \newline.	  If multiple here documents are used on the same com-
	      mand line, they are saved	in order.

       <<- marker
	      same as <<, except leading tabs are stripped from	lines  in  the
	      here document.

       <& fd  standard input is	duplicated from	file descriptor	fd.  fd	can be
	      a	single digit, indicating the number of an  existing  file  de-
	      scriptor,	 the  letter p,	indicating the file descriptor associ-
	      ated with	the output of the current co-process, or the character
	      -, indicating standard input is to be closed.

       >& fd  same as <&, except the operation is done on standard output.

       In  any	of  the	 above redirections, the file descriptor that is redi-
       rected (i.e., standard input or	standard  output)  can	be  explicitly
       given  by  preceding  the  redirection with a single digit.  Parameter,
       command and arithmetic substitutions, tilde substitutions and  (if  the
       shell  is  interactive)	file  name generation are all performed	on the
       file, marker and	fd arguments of	redirections.  Note however, that  the
       results	of  any	file name generation are only used if a	single file is
       matched;	if multiple files match, the word  with	 the  unexpanded  file
       name  generation	 characters  is	used.  Note that in restricted shells,
       redirections which can create files cannot be used.

       For simple-commands, redirections may appear anywhere in	 the  command,
       for  compound-commands (if statements, etc.), any redirections must ap-
       pear at the end.	 Redirections are processed after pipelines  are  cre-
       ated and	in the order they are given, so
	      cat /foo/bar 2>&1	> /dev/null | cat -n
       will print an error with	a line number prepended	to it.

   Arithmetic Expressions
       Integer arithmetic expressions can be used with the let command,	inside
       $((..)) expressions, inside array references (e.g., name[expr]),	as nu-
       meric  arguments	to the test command, and as the	value of an assignment
       to an integer parameter.

       Expression may contain alpha-numeric parameter identifiers, array  ref-
       erences,	and integer constants and may be combined with the following C
       operators (listed and grouped in	increasing order of precedence).

       Unary operators:
	      +	- ! ~ ++ --

       Binary operators:
	      =	*= /= %= += -= <<= >>= &= ^= |=
	      == !=
	      <	<= >= >
	      << >>
	      +	-
	      *	/ %

       Ternary operator:
	      ?: (precedence is	immediately higher than	assignment)

       Grouping	operators:
	      (	)

       Integer constants may be	specified with arbitrary bases using the nota-
       tion  base#number, where	base is	a decimal integer specifying the base,
       and number is a number in the specified base.

       The operators are evaluated as follows:

	      unary +
		     result is the argument (included for completeness).

	      unary -

	      !	     logical not; the result is	1 if argument is  zero,	 0  if

	      ~	     arithmetic	(bit-wise) not.

	      ++     increment;	 must be applied to a parameter	(not a literal
		     or	other expression) - the	parameter is incremented by 1.
		     When  used	as a prefix operator, the result is the	incre-
		     mented value of the parameter, when used as a postfix op-
		     erator,  the  result is the original value	of the parame-

	      --     similar to	++, except the parameter is decremented	by 1.

	      ,	     separates two arithmetic expressions; the left hand  side
		     is	 evaluated first, then the right.  The result is value
		     of	the expression on the right hand side.

	      =	     assignment; variable on the left is set to	the  value  on
		     the right.

	      *= /= %= += -= <<= >>= &=	^= |=
		     assignment	 operators;  _var_ _op_= _expr_	is the same as
		     _var_ = _var_ _op_	( _expr_ ).

	      ||     logical or; the result is 1 if either  argument  is  non-
		     zero,  0 if not.  The right argument is evaluated only if
		     the left argument is zero.

	      &&     logical and; the result is	1 if both arguments  are  non-
		     zero,  0 if not.  The right argument is evaluated only if
		     the left argument is non-zero.

	      |	     arithmetic	(bit-wise) or.

	      ^	     arithmetic	(bit-wise) exclusive-or.

	      &	     arithmetic	(bit-wise) and.

	      ==     equal; the	result is 1 if both arguments are equal, 0  if

	      !=     not equal;	the result is 0	if both	arguments are equal, 1
		     if	not.

	      <	     less than;	the result is 1	if the left argument  is  less
		     than the right, 0 if not.

	      <= >= >
		     less  than	or equal, greater than or equal, greater than.
		     See <.

	      << >>  shift left	(right); the result is the left	argument  with
		     its  bits shifted left (right) by the amount given	in the
		     right argument.

	      +	- * /
		     addition, subtraction, multiplication, and	division.

	      %	     remainder;	the result is the remainder of the division of
		     the  left	argument by the	right.	The sign of the	result
		     is	unspecified if either argument is negative.

	      _arg1_ ? _arg2_ :	_arg3_
		     if	_arg1_ is non-zero, the	result	is  _arg2_,  otherwise

       A  co-process,  which is	a pipeline created with	the |& operator, is an
       asynchronous process that the shell can both write to (using print  -p)
       and  read from (using read -p).	The input and output of	the co-process
       can also	be manipulated using >&p and <&p  redirections,	 respectively.
       Once  a co-process has been started, another can't be started until the
       co-process exits, or until the co-process input has been	redirected us-
       ing an exec n>&p	redirection.  If a co-process's	input is redirected in
       this way, the next co-process to	be started will	share the output  with
       the  first  co-process, unless the output of the	initial	co-process has
       been redirected using an	exec n<&p redirection.

       Some notes concerning co-processes:
	 o    the only way to close the	co-process input  (so  the  co-process
	      reads  an	 end-of-file)  is  to redirect the input to a numbered
	      file descriptor and then close that file descriptor (e.g.,  exec
	      3>&p;exec	3>&-).
	 o    in  order	 for  co-processes to share a common output, the shell
	      must keep	the write portion of the output	pipe open.  This means
	      that  end	 of  file  will	not be detected	until all co-processes
	      sharing the co-process output have exited	(when they  all	 exit,
	      the  shell closes	its copy of the	pipe).	This can be avoided by
	      redirecting the output to	a numbered file	 descriptor  (as  this
	      also causes the shell to close its copy).	 Note that this	behav-
	      iour is slightly different from the original  Korn  shell	 which
	      closes its copy of the write portion of the co-processes'	output
	      when the most recently started co-process	(instead of  when  all
	      sharing co-processes) exits.
	 o    print -p will ignore SIGPIPE signals during writes if the	signal
	      is not being trapped or ignored; the same	is not true if the co-
	      process input has	been duplicated	to another file	descriptor and
	      print -un	is used.

       Functions are defined using either Korn shell function name  syntax  or
       the  Bourne/POSIX shell name() syntax (see below	for the	difference be-
       tween the two forms).  Functions	are like .-scripts in  that  they  are
       executed	 in  the current environment, however, unlike .-scripts, shell
       arguments (i.e.,	positional parameters, $1, etc.) are never visible in-
       side  them.   When  the shell is	determining the	location of a command,
       functions are searched after special built-in commands, and before reg-
       ular and	non-regular built-ins, and before the PATH is searched.

       An  existing  function  may be deleted using unset -f function-name.  A
       list of functions can be	obtained using typeset	+f  and	 the  function
       definitions  can	 be  listed  using  typeset -f.	 autoload (which is an
       alias for typeset -fu) may be used to create undefined functions;  when
       an  undefined  function is executed, the	shell searches the path	speci-
       fied in the FPATH parameter for a file with the same name as the	 func-
       tion,  which,  if  found	 is read and executed.	If after executing the
       file, the named function	is found to be defined,	the function  is  exe-
       cuted,  otherwise,  the	normal	command	search is continued (i.e., the
       shell searches the regular built-in command table and PATH).  Note that
       if  a command is	not found using	PATH, an attempt is made to autoload a
       function	using FPATH (this is an	undocumented feature of	 the  original
       Korn shell).

       Functions  can  have two	attributes, trace and export, which can	be set
       with typeset -ft	and typeset -fx, respectively.	When a traced function
       is  executed,  the shell's xtrace option	is turned on for the functions
       duration, otherwise the xtrace option is	turned off.  The export	attri-
       bute  of	 functions is currently	not used.  In the original Korn	shell,
       exported	functions are visible to shell scripts that are	executed.

       Since functions are executed in the current shell environment,  parame-
       ter  assignments	 made  inside functions	are visible after the function
       completes.  If this is not the desired effect, the typeset command  can
       be  used	inside a function to create a local parameter.	Note that spe-
       cial parameters (e.g., $$, $!) can't be scoped in this way.

       The exit	status of a function is	that of	the last command  executed  in
       the  function.	A function can be made to finish immediately using the
       return command; this may	also be	used to	explicitly  specify  the  exit

       Functions  defined  with	the function reserved word are treated differ-
       ently in	the following ways from	functions defined with	the  ()	 nota-
	 o    the  $0  parameter  is  set to the name of the function (Bourne-
	      style functions leave $0 untouched).
	 o    parameter	assignments preceding function calls are not  kept  in
	      the  shell  environment  (executing  Bourne-style	functions will
	      keep assignments).
	 o    OPTIND is	saved/reset and	restored on entry and  exit  from  the
	      function so getopts can be used properly both inside and outside
	      the function (Bourne-style functions leave OPTIND	untouched,  so
	      using  getopts  inside  a	function interferes with using getopts
	      outside the function).  In the future, the following differences
	      will also	be added:
	 o    A	 separate trap/signal environment will be used during the exe-
	      cution of	functions.  This will mean that	 traps	set  inside  a
	      function	will not affect	the shell's traps and signals that are
	      not ignored in the shell (but may	be trapped)  will  have	 their
	      default effect in	a function.
	 o    The  EXIT	trap, if set in	a function, will be executed after the
	      function returns.

   POSIX Mode
       The shell is intended to	be POSIX compliant, however,  in  some	cases,
       POSIX behaviour is contrary either to the original Korn shell behaviour
       or to user convenience.	How the	shell behaves in these cases is	deter-
       mined  by  the state of the posix option	(set -o	posix) -- if it	is on,
       the POSIX behaviour is followed,	otherwise it is	not.  The posix	option
       is  set	automatically when the shell starts up if the environment con-
       tains the POSIXLY_CORRECT parameter.  (The shell	can also  be  compiled
       so that it is in	POSIX mode by default, however this is usually not de-

       The following is	a list of things that are affected by the state	of the
       posix option:
	 o    kill  -l	output:	 in  posix mode, signal	names are listed one a
	      single line; in non-posix	mode, signal numbers,  names  and  de-
	      scriptions  are printed in columns.  In future, a	new option (-v
	      perhaps) will be added to	distinguish the	two behaviours.
	 o    fg exit status: in posix mode, the exit status is	0 if no	errors
	      occur;  in  non-posix  mode, the exit status is that of the last
	      foregrounded job.
	 o    eval exit	status:	if eval	gets to	see an	empty  command	(e.g.,
	      eval  "`false`"),	 its  exit status in posix mode	will be	0.  In
	      non-posix	mode, it will be the exit status of the	 last  command
	      substitution that	was done in the	processing of the arguments to
	      eval (or 0 if there were no command substitutions).
	 o    getopts: in posix	mode, options must start with  a  -;  in  non-
	      posix mode, options can start with either	- or +.
	 o    brace  expansion	(also  known  as  alternation):	in posix mode,
	      brace expansion is disabled; in non-posix	mode, brace  expansion
	      enabled.	Note that set -o posix (or setting the POSIXLY_CORRECT
	      parameter) automatically turns the braceexpand option off,  how-
	      ever it can be explicitly	turned on later.
	 o    set  -: in posix mode, this does not clear the verbose or	xtrace
	      options; in non-posix mode, it does.
	 o    set exit status: in posix	mode, the exit status of set is	 0  if
	      there  are no errors; in non-posix mode, the exit	status is that
	      of any command substitutions performed  in  generating  the  set
	      command.	 For  example,	`set  -- `false`; echo $?' prints 0 in
	      posix mode, 1 in non-posix mode.	This construct is used in most
	      shell scripts that use the old getopt(1) command.
	 o    argument	expansion of alias, export, readonly, and typeset com-
	      mands: in	posix mode, normal argument expansion  done;  in  non-
	      posix  mode,  field splitting, file globing, brace expansion and
	      (normal) tilde expansion are turned off,	and  assignment	 tilde
	      expansion	is turned on.
	 o    signal specification: in posix mode, signals can be specified as
	      digits only if signal numbers match POSIX	values	(i.e.,	HUP=1,
	      INT=2,  QUIT=3,  ABRT=6,	KILL=9,	ALRM=14, and TERM=15); in non-
	      posix mode, signals can be always	digits.
	 o    alias expansion: in posix	mode, alias expansion is only  carried
	      out  when	reading	command	words; in non-posix mode, alias	expan-
	      sion is carried out on any word following	an alias that ended in
	      a	space.	For example, the following for loop
	      alias a='for ' i='j'
	      a	i in 1 2; do echo i=$i j=$j; done
       uses parameter i	in posix mode, j in non-posix mode.
	 o    test:  in	posix mode, the	expression "-t"	(preceded by some num-
	      ber of "!" arguments) is always true as it is a non-zero	length
	      string;  in  non-posix  mode, it tests if	file descriptor	1 is a
	      tty (i.e., the fd	argument to the	-t test	may be	left  out  and
	      defaults to 1).

   Command Execution
       After  evaluation of command line arguments, redirections and parameter
       assignments, the	type of	command	is determined: a special  built-in,  a
       function, a regular built-in or the name	of a file to execute found us-
       ing the PATH parameter.	The checks are made in the above order.	  Spe-
       cial  built-in commands differ from other commands in that the PATH pa-
       rameter is not used to find them, an error during their	execution  can
       cause  a	 non-interactive  shell	to exit	and parameter assignments that
       are specified before the	command	are kept after the command  completes.
       Just to confuse things, if the posix option is turned off (see set com-
       mand below) some	special	commands are very special  in  that  no	 field
       splitting,  file	 globing,  brace expansion nor tilde expansion is per-
       formed on arguments that	look like assignments.	Regular	built-in  com-
       mands are different only	in that	the PATH parameter is not used to find

       The original ksh	and POSIX differ somewhat in which commands  are  con-
       sidered special or regular:

       POSIX special commands

	      .		 continue   exit       return	  trap
	      :		 eval	    export     set	  unset
	      break	 exec	    readonly   shift

       Additional ksh special commands

	      builtin	 times	    typeset

       Very special commands (non-posix	mode)

	      alias	 readonly   set	       typeset

       POSIX regular commands

	      alias	 command    fg	       kill	  umask
	      bg	 false	    getopts    read	  unalias
	      cd	 fc	    jobs       true	  wait

       Additional ksh regular commands

	      [		 let	    pwd	       ulimit
	      echo	 print	    test       whence

       In  the	future,	the additional ksh special and regular commands	may be
       treated differently from	the POSIX special and regular commands.

       Once the	type of	the command has	been determined, any command line  pa-
       rameter	assignments are	performed and exported for the duration	of the

       The following describes the special and regular built-in	commands:

       . file [arg1 ...]
	      Execute the commands in file in the  current  environment.   The
	      file  is	searched for in	the directories	of PATH.  If arguments
	      are given, the positional	parameters may be used to access  them
	      while  file  is  being executed.	If no arguments	are given, the
	      positional parameters are	those of the environment  the  command
	      is used in.

       : [ ... ]
	      The null command.	 Exit status is	set to zero.

       alias [ -d | +-t	[-r] ] [+-px] [+-] [name1[=value1] ...]
	      Without  arguments, alias	lists all aliases.  For	any name with-
	      out a value, the existing	alias is  listed.   Any	 name  with  a
	      value defines an alias (see Aliases above).

	      When  listing  aliases,  one  of	two formats is used: normally,
	      aliases are listed as name=value,	where value is quoted; if  op-
	      tions  were  preceded with + or a	lone + is given	on the command
	      line, only name is printed.  In addition,	if the	-p  option  is
	      used, each alias is prefixed with	the string "alias ".

	      The -x option sets (+x clears) the export	attribute of an	alias,
	      or, if no	names are given, lists the aliases with	the export at-
	      tribute (exporting an alias has no affect).

	      The   -t	option	indicates  that	 tracked  aliases  are	to  be
	      listed/set (values specified on the command line are ignored for
	      tracked  aliases).   The	-r  option  indicates that all tracked
	      aliases are to be	reset.

	      The -d causes directory aliases, which are used in tilde	expan-
	      sion, to be listed or set	(see Tilde Expansion above).

       bg [job ...]
	      Resume  the  specified  stopped job(s) in	the background.	 If no
	      jobs are specified, %+ is	assumed.  This command is only	avail-
	      able  on systems which support job control.  See Job Control be-
	      low for more information.

       bind [-l] [-m] [key[=editing-command] ...]
	      Set  or  view  the  current  emacs  command  editing  key	 bind-
	      ings/macros.   See  Emacs	 Editing Mode below for	a complete de-

       break [level]
	      break exits the levelth inner most for, select, until, or	 while
	      loop.  level defaults to 1.

       builtin command [arg1 ...]
	      Execute the built-in command command.

       cd [-LP]	[dir]
	      Set  the	working	 directory to dir.  If the parameter CDPATH is
	      set, it lists directories	to search in for dir.  An empty	 entry
	      in the CDPATH entry means	the current directory.	If a non-empty
	      directory	from CDPATH  is	 used,	the  resulting	full  path  is
	      printed  to standard output.  If dir is missing, the home	direc-
	      tory $HOME is used.  If dir is -,	the previous working directory
	      is  used (see OLDPWD parameter).	If -L option (logical path) is
	      used or if the physical option (see  set	command	 below)	 isn't
	      set,  references	to .. in dir are relative to the path used get
	      to the directory.	 If -P option (physical	path) is  used	or  if
	      the physical option is set, .. is	relative to the	filesystem di-
	      rectory tree.  The PWD and OLDPWD	parameters are updated to  re-
	      flect the	current	and old	wording	directory, respectively.

       cd [-LP]	old new
	      The  string new is substituted for old in	the current directory,
	      and the shell attempts to	change to the new directory.

       command [-pvV] cmd [arg1	...]
	      If neither the -v	nor -V options are given, cmd is executed  ex-
	      actly  as	if the command had not been specified, with two	excep-
	      tions: first, cmd	cannot be a shell function, and	 second,  spe-
	      cial built-in commands lose their	specialness (i.e., redirection
	      and utility errors do not	cause the shell	to exit,  and  command
	      assignments  are	not  permanent).  If the -p option is given, a
	      default search path is used instead of the current value of PATH
	      (the  actual  value  of the default path is system dependent: on
	      POSIXish systems,	it is the value	returned by
				      getconf CS_PATH

	      If the -v	option is given, instead of executing cmd, information
	      about  what would	be executed is given (and the same is done for
	      arg1 ...): for special and regular built-in commands  and	 func-
	      tions,  their  names  are	simply printed,	for aliases, a command
	      that defines them	is printed, and	for commands found by  search-
	      ing the PATH parameter, the full path of the command is printed.
	      If no command is found, (i.e., the path search  fails),  nothing
	      is printed and command exits with	a non-zero status.  The	-V op-
	      tion is like the -v option, except it is more verbose.

       continue	[levels]
	      continue jumps to	the beginning of the levelth inner  most  for,
	      select, until, or	while loop.  level defaults to 1.

       echo [-neE] [arg	...]
	      Prints  its  arguments  (separated by spaces) followed by	a new-
	      line, to standard	out.  The newline is suppressed	if any of  the
	      arguments	 contain the backslash sequence	\c.  See print command
	      below for	a list of other	backslash sequences  that  are	recog-

	      The  options  are	 provided  for	compatibility  with  BSD shell
	      scripts: -n suppresses the trailing newline,  -e	enables	 back-
	      slash interpretation (a no-op, since this	is normally done), and
	      -E suppresses backslash interpretation.

       eval command ...
	      The arguments are	concatenated (with  spaces  between  them)  to
	      form a single string which the shell then	parses and executes in
	      the current environment.

       exec [command [arg ...]]
	      The command is executed without  forking,	 replacing  the	 shell

	      If  no  arguments	are given, any IO redirection is permanent and
	      the shell	is not replaced.  Any file descriptors greater than  2
	      which are	opened or dup(2)-ed in this way	are not	made available
	      to other executed	commands (i.e.,	commands that are not built-in
	      to the shell).  Note that	the Bourne shell differs here: it does
	      pass these file descriptors on.

       exit [status]
	      The shell	exits with the specified exit status.	If  status  is
	      not specified, the exit status is	the current value of the ? pa-

       export [-p] [parameter[=value]] ...
	      Sets the export attribute	of the named parameters.  Exported pa-
	      rameters are passed in the environment to	executed commands.  If
	      values are specified, the	named parameters also assigned.

	      If no parameters are specified, the names	of all parameters with
	      the export attribute are printed one per line, unless the	-p op-
	      tion is used, in which case export  commands  defining  all  ex-
	      ported parameters, including their values, are printed.

       false  A	command	that exits with	a non-zero status.

       fc [-e editor | -l [-n]]	[-r] [first [last]]
	      first  and  last select commands from the	history.  Commands can
	      be selected by history number, or	a string specifying  the  most
	      recent  command  starting	with that string.  The -l option lists
	      the command on stdout, and -n inhibits the default command  num-
	      bers.   The  -r  option reverses the order of the	list.  Without
	      -l, the selected commands	are edited  by	the  editor  specified
	      with  the	-e option, or if no -e is specified, the editor	speci-
	      fied by the FCEDIT parameter (if	this  parameter	 is  not  set,
	      /bin/ed is used),	and then executed by the shell.

       fc [-e -	| -s] [-g] [old=new] [prefix]
	      Re-execute  the  selected	 command  (the previous	command	by de-
	      fault) after performing the optional substitution	 of  old  with
	      new.   If	 -g  is	specified, all occurrences of old are replaced
	      with new.	 This command is usually accessed with the  predefined
	      alias r='fc -e -'.

       fg [job ...]
	      Resume  the  specified job(s) in the foreground.	If no jobs are
	      specified, %+ is assumed.	 This command  is  only	 available  on
	      systems  which  support  job control.  See Job Control below for
	      more information.

       getopts optstring name [arg ...]
	      getopts is used by shell procedures to parse the specified argu-
	      ments  (or positional parameters,	if no arguments	are given) and
	      to check for legal options.  optstring contains the option  let-
	      ters that	getopts	is to recognize.  If a letter is followed by a
	      colon, the option	is expected to have an argument.  Options that
	      do  not  take arguments may be grouped in	a single argument.  If
	      an option	takes an argument and the option character is not  the
	      last  character of the argument it is found in, the remainder of
	      the argument is taken to be the  option's	 argument,  otherwise,
	      the next argument	is the option's	argument.

	      Each  time  getopts is invoked, it places	the next option	in the
	      shell parameter name and the index of the	next  argument	to  be
	      processed	 in the	shell parameter	OPTIND.	 If the	option was in-
	      troduced with a +, the option placed in name is prefixed with  a
	      +.   When	 an  option requires an	argument, getopts places it in
	      the shell	parameter OPTARG.  When	an illegal option or a missing
	      option  argument	is  encountered	 a question mark or a colon is
	      placed in	name (indicating an illegal option  or	missing	 argu-
	      ment,  respectively)  and	 OPTARG	is set to the option character
	      that caused the problem.	An error message is  also  printed  to
	      standard error if	optstring does not begin with a	colon.

	      When the end of the options is encountered, getopts exits	with a
	      non-zero exit status.  Options end at the	first (non-option) ar-
	      gument  that  does  not start with a -, or when a	-- argument is

	      Option parsing can be reset by setting OPTIND to 1 (this is done
	      automatically  whenever  the  shell  or a	shell procedure	is in-

	      Warning: Changing	the value of the shell parameter OPTIND	 to  a
	      value other than 1, or parsing different sets of arguments with-
	      out resetting OPTIND may lead to unexpected results.

       hash [-r] [name ...]
	      Without arguments, any hashed executable command	pathnames  are
	      listed.	The -r option causes all hashed	commands to be removed
	      from the hash table.  Each name is searched as  if  it  where  a
	      command  name and	added to the hash table	if it is an executable

       jobs [-lpn] [job	...]
	      Display information about	the specified jobs;  if	 no  jobs  are
	      specified,  all jobs are displayed.  The -n option causes	infor-
	      mation to	be displayed only for jobs  that  have	changed	 state
	      since  the  last	notification.	If  the	-l option is used, the
	      process-id of each process in a job is also listed.  The -p  op-
	      tion  causes  only  the process group of each job	to be printed.
	      See Job Control below for	the format of job  and	the  displayed

       kill [-s	signame	| -signum | -signame ] { job | pid | -pgrp } ...
	      Send the specified signal	to the specified jobs, process ids, or
	      process groups.  If no signal is specified, the signal  TERM  is
	      sent.   If  a  job is specified, the signal is sent to the job's
	      process group.  See Job Control below for	the format of job.

       kill -l [exit-status ...]
	      Print the	name of	the signal that	killed a process which	exited
	      with  the	 specified  exit-statuses.  If no arguments are	speci-
	      fied, a list of all the signals, their numbers and a  short  de-
	      scription	of them	are printed.

       let [expression ...]
	      Each  expression is evaluated, see Arithmetic Expressions	above.
	      If all expressions are successfully evaluated, the  exit	status
	      is  0  (1)  if the last expression evaluated to non-zero (zero).
	      If an error occurs during	the parsing or evaluation  of  an  ex-
	      pression,	 the exit status is greater than 1.  Since expressions
	      may need to be quoted, ((	expr ))	is  syntactic  sugar  for  let

       print [-nprsun |	-R [-en]] [argument ...]
	      Print  prints its	arguments on the standard output, separated by
	      spaces, and terminated with a newline.  The -n option suppresses
	      the  newline.   By  default,  certain  C escapes are translated.
	      These include \b,	\f, \n,	\r, \t,	\v, and	\0### (# is  an	 octal
	      digit, of	which there may	be 0 to	3).  \c	is equivalent to using
	      the -n option.  \	expansion may be inhibited with	the -r option.
	      The  -s  option  prints  to the history file instead of standard
	      output, the -u option prints to file descriptor n	(n defaults to
	      1	 if  omitted), and the -p option prints	to the co-process (see
	      Co-Processes above).

	      The -R option is used to emulate,	to some	degree,	the  BSD  echo
	      command, which does not process \	sequences unless the -e	option
	      is given.	 As above, the -n option suppresses the	trailing  new-

       pwd [-LP]
	      Print the	present	working	directory.  If -L option is used or if
	      the physical option (see set command below) isn't	set, the logi-
	      cal  path	 is  printed (i.e., the	path used to cd	to the current
	      directory).  If -P option	(physical path)	 is  used  or  if  the
	      physical	option is set, the path	determined from	the filesystem
	      (by following ..	directories to the root	directory) is printed.

       read [-prsun] [parameter	...]
	      Reads a line of input from standard  input,  separate  the  line
	      into  fields  using  the IFS parameter (see Substitution above),
	      and assign each field to the specified parameters.  If there are
	      more  parameters	than  fields,  the extra parameters are	set to
	      null, or alternatively, if there are more	 fields	 than  parame-
	      ters,  the  last parameter is assigned the remaining fields (in-
	      clusive of any separating	spaces).  If no	parameters are	speci-
	      fied,  the REPLY parameter is used.  If the input	line ends in a
	      backslash	and the	-r option was not used,	the backslash and new-
	      line  are	stripped and more input	is read.  If no	input is read,
	      read exits with a	non-zero status.

	      The first	parameter may have a question mark and	a  string  ap-
	      pended  to  it,  in  which  case	the string is used as a	prompt
	      (printed to standard error before	any input is read) if the  in-
	      put is a tty (e.g., read nfoo?'number of foos: ').

	      The -un and -p options cause input to be read from file descrip-
	      tor n or the current co-process (see Co-Processes	above for com-
	      ments  on	 this),	respectively.  If the -s option	is used, input
	      is saved to the history file.

       readonly	[-p] [parameter[=value]] ...
	      Sets the readonly	attribute of the named parameters.  If	values
	      are  given, parameters are set to	them before setting the	attri-
	      bute.  Once a parameter is made readonly,	it cannot be unset and
	      its value	cannot be changed.

	      If no parameters are specified, the names	of all parameters with
	      the readonly attribute are printed one per line, unless  the  -p
	      option  is  used,	 in  which case	readonly commands defining all
	      readonly parameters, including their values, are printed.

       return [status]
	      Returns from a function or . script, with	 exit  status  status.
	      If no status is given, the exit status of	the last executed com-
	      mand is used.  If	used outside of	a function or .	script,	it has
	      the  same	 effect	 as exit.  Note	that pdksh treats both profile
	      and $ENV files as	. scripts, while the original Korn shell  only
	      treats profiles as . scripts.

       set [+-abCefhkmnpsuvxX] [+-o [option]] [+-A name] [--] [arg ...]
	      The  set	command	 can be	used to	set (-)	or clear (+) shell op-
	      tions, set the positional	parameters, or set an array parameter.
	      Options can be changed using the +-o option syntax, where	option
	      is the long name of an option, or	 using	the  +-letter  syntax,
	      where letter is the option's single letter name (not all options
	      have a single letter name).  The following table lists both  op-
	      tion  letters  (if  they	exist) and long	names along with a de-
	      scription	of what	the option does.

	       -A				Sets the elements of the array
						parameter  name	to arg ...; If
						-A is used, the	array is reset
						(i.e.,	emptied)  first; if +A
						is used, the first N  elements
						are set	(where N is the	number
						of args), the  rest  are  left
	       -a	  allexport		all new	parameters are created
						with the export	attribute
	       -b	  notify		Print  job  notification  mes-
						sages  asynchronously, instead
						of  just  before  the  prompt.
						Only  used  if	job control is
						enabled	(-m).
	       -C	  noclobber		Prevent	 >  redirection	  from
						overwriting existing files (>|
						must be	used to	force an over-
	       -e	  errexit		Exit  (after executing the ERR
						trap) as soon as an error  oc-
						curs or	a command fails	(i.e.,
						exits with a non-zero status).
						This  does  not	 apply to com-
						mands whose exit status	is ex-
						plicitly  tested  by  a	 shell
						construct such as  if,	until,
						while, && or ||	statements.
	       -f	  noglob		Do  not	 expand	file name pat-
	       -h	  trackall		Create tracked aliases for all
						executed commands (see Aliases
						above).	  On  by  default  for
						non-interactive	shells.
	       -i	  interactive		Enable interactive mode	- this
						can only be set/unset when the
						shell is invoked.
	       -k	  keyword		Parameter assignments are rec-
						ognized	anywhere in a command.
	       -l	  login			The shell is a login  shell  -
						this  can  only	 be  set/unset
						when the shell is invoked (see
						Shell Startup above).
	       -m	  monitor		Enable	job  control  (default
						for interactive	shells).
	       -n	  noexec		Do not execute any commands  -
						useful for checking the	syntax
						of scripts (ignored if	inter-
	       -p	  privileged		Set automatically if, when the
						shell starts, the real uid  or
						gid  does not match the	effec-
						tive uid or gid, respectively.
						See  Shell Startup above for a
						description   of   what	  this
	       -r	  restricted		Enable restricted mode -- this
						option can only	be  used  when
						the  shell  is	invoked.   See
						Shell Startup above for	a  de-
						scription of what this means.

	       -s	  stdin			If  used when the shell	is in-
						voked, commands	are read  from
						standard input.	 Set automati-
						cally if the shell is  invoked
						with no	arguments.

						When  -s  is  used  in the set
						command, it causes the	speci-
						fied  arguments	 to  be	sorted
						before assigning them  to  the
						positional  parameters	(or to
						array name, if -A is used).
	       -u	  nounset		Referencing of an unset	param-
						eter  is  treated as an	error,
						unless one of the -,  +	 or  =
						modifiers is used.
	       -v	  verbose		Write  shell input to standard
						error as it is read.
	       -x	  xtrace		Print commands	and  parameter
						assignments when they are exe-
						cuted, preceded	by  the	 value
						of PS4.
	       -X	  markdirs		Mark directories with a	trail-
						ing / during file name genera-
			  bgnice		Background  jobs  are run with
						lower priority.
			  braceexpand		Enable brace  expansion	 (aka,
			  emacs			Enable	BRL emacs-like command
						line   editing	  (interactive
						shells	only); see Emacs Edit-
						ing Mode.
			  emacs-usemeta		In emacs command-line editing,
						use  the  8th bit as meta (^[)
						prefix.	 This is  the  default
						if  LC_CTYPE is	unset or POSIX
						respectively C.	 8
			  gmacs			Enable	 gmacs-like   (Gosling
						emacs)	command	 line  editing
						(interactive   shells	only);
						currently  identical  to emacs
						editing	except that  transpose
						(^T)   acts  slightly  differ-
			  ignoreeof		The shell  will	 not  (easily)
						exit  on  when	end-of-file is
						read, exit must	be  used.   To
						avoid	infinite   loops,  the
						shell will exit	if eof is read
						13 times in a row.
			  nohup			Do  not	kill running jobs with
						a  HUP	signal	when  a	 login
						shell  exists.	 Currently set
						by  default,  but  this	  will
						change	in  the	 future	 to be
						compatible with	 the  original
						Korn shell (which doesn't have
						this option, but does send the
						HUP signal).
			  nolog			No  effect  -  in the original
						Korn  shell,   this   prevents
						function  definitions from be-
						ing  stored  in	 the   history

			  physical		Causes the cd and pwd commands
						to use `physical'  (i.e.,  the
						filesystem's)  ..  directories
						instead	of `logical'  directo-
						ries (i.e.,  the shell handles
						.., which allows the  user  to
						be  oblivious of symlink links
						to directories).  Clear	by de-
						fault.	Note that setting this
						option	does  not  effect  the
						current	 value	of the PWD pa-
						rameter; only the  cd  command
						changes	 PWD.	See the	cd and
						pwd commands  above  for  more
			  posix			Enable	posix mode.  See POSIX
						Mode above.
			  vi			Enable	vi-like	 command  line
						editing	  (interactive	shells
			  viraw			No effect -  in	 the  original
						Korn  shell,  unless viraw was
						set, the vi command line  mode
						would  let  the	 tty driver do
						the work until	ESC  (^[)  was
						entered.   pdksh  is always in
						viraw mode.
			  vi-esccomplete	In vi command line editing, do
						command	/ file name completion
						when escape (^[) is entered in
						command	mode.
			  vi-show8		Prefix	 characters  with  the
						eighth bit set with `M-'.   If
						this  option is	not set, char-
						acters in  the	range  128-160
						are  printed  as is, which may
						cause problems.
			  vi-tabcomplete	In vi command line editing, do
						command	/ file name completion
						when tab (^I)  is  entered  in
						insert	mode.  This is the de-

	      These options can	also be	used upon  invocation  of  the	shell.
	      The  current  set	 of  options (with single letter names)	can be
	      found in the parameter -.	 set -o	with no	option name will  list
	      all the options and whether each is on or	off; set +o will print
	      the long names of	all options that are currently on.

	      Remaining	arguments, if any, are positional parameters  and  are
	      assigned,	 in  order,  to	the positional parameters (i.e., 1, 2,
	      etc.).  If options are ended with	-- and there are no  remaining
	      arguments, all positional	parameters are cleared.	 If no options
	      or arguments are	given,	then  the  values  of  all  names  are
	      printed.	 For  unknown  historical  reasons, a lone - option is
	      treated specially: it clears both	the -x and -v options.

       shift [number]
	      The positional parameters	number+1, number+2 etc.	are renamed to
	      1, 2, etc.  number defaults to 1.

       test expression

       [ expression ]
	      test evaluates the expression and	returns	zero status if true, 1
	      if false,	and greater than 1 if there was	an error.  It is  nor-
	      mally  used as the condition command of if and while statements.
	      The following basic expressions are available:

	       str		    str	has non-zero  length.	Note
				    that  there	is the potential for
				    problems if	str turns out to  be
				    an	operator  (e.g., -r) - it is
				    generally better to	use  a	test
					    [ X"str" !=	X ]
				    instead  (double quotes are	used
				    in case str	contains  spaces  or
				    file globing characters).
	       -r file		    file exists	and is readable.
	       -w file		    file exists	and is writable.
	       -x file		    file exists	and is executable.
	       -a file		    file exists.
	       -e file		    file exists.
	       -f file		    file is a regular file.
	       -d file		    file is a directory.
	       -c file		    file  is a character special de-
	       -b file		    file is a block special device.
	       -p file		    file is a named pipe.
	       -u file		    file's mode	has setuid bit set.
	       -g file		    file's mode	has setgid bit set.
	       -k file		    file's mode	has sticky bit set.
	       -s file		    file is not	empty.
	       -O file		    file's owner is the	shell's	 ef-
				    fective user-ID.
	       -G file		    file's  group is the shell's ef-
				    fective group-ID.
	       -h file		    file is a symbolic link.
	       -H file		    file is a context dependent	 di-
				    rectory (only useful on HP-UX).
	       -L file		    file is a symbolic link.
	       -S file		    file is a socket.
	       -o option	    shell  option  is  set  (see set
				    command above for  list  of	 op-
				    tions).   As  a non-standard ex-
				    tension, if	 the  option  starts
				    with  a  !,	the test is negated;
				    the	test always fails if  option
				    doesn't exist (thus
					 [ -o foo -o -o	!foo ]
				    returns  true if and only if op-
				    tion foo exists).
	       file -nt	file	    first file is newer	than  second
				    file  or  first  file exists and
				    the	second file does not.
	       file -ot	file	    first file is older	than  second
				    file  or  second file exists and
				    the	first file does	not.
	       file -ef	file	    first file is the same  file  as
				    second file.
	       -t [fd]		    file descriptor is a tty device.
				    If	the  posix  option  (set  -o
				    posix,  see	POSIX Mode above) is
				    not	set, fd	may be left out,  in
				    which  case	 it is taken to	be 1
				    (the behaviour  differs  due  to
				    the	  special  POSIX  rules	 de-
				    scribed below).
	       string		    string is not empty.
	       -z string	    string is empty.
	       -n string	    string is not empty.
	       string =	string	    strings are	equal.
	       string == string	    strings are	equal.
	       string != string	    strings are	not equal.
	       number -eq number    numbers compare equal.
	       number -ne number    numbers compare not	equal.

	       number -ge number    numbers compare greater than  or
	       number -gt number    numbers compare greater than.
	       number -le number    numbers  compare  less  than  or
	       number -lt number    numbers compare less than.

	      The above	basic  expressions,  in	 which	unary  operators  have
	      precedence  over binary operators, may be	combined with the fol-
	      lowing operators (listed in increasing order of precedence):

	       expr -o expr    logical or
	       expr -a expr    logical and
	       ! expr	       logical not
	       ( expr )	       grouping

	      On operating systems not supporting /dev/fd/n devices  (where  n
	      is  a  file descriptor number), the test command will attempt to
	      fake it for all tests that  operate  on  files  (except  the  -e
	      test).   I.e.,  [	 -w  /dev/fd/2 ] tests if file descriptor 2 is

	      Note that	some special rules are applied (courtesy of POSIX)  if
	      the number of arguments to test or [ ... ] is less than five: if
	      leading !	arguments can be stripped such that only one  argument
	      remains  then  a string length test is performed (again, even if
	      the argument is a	unary operator); if leading ! arguments	can be
	      stripped	such  that three arguments remain and the second argu-
	      ment is a	binary operator, then the  binary  operation  is  per-
	      formed (even if first argument is	a unary	operator, including an
	      unstripped !).

	      Note: A common mistake is	to use if [ $foo = bar ]  which	 fails
	      if  parameter  foo  is  null or unset, if	it has embedded	spaces
	      (i.e., IFS characters), or if it is a unary operator like	 !  or
	      -n.  Use tests like if [ "X$foo" = Xbar ]	instead.

       time [-p] [ pipeline ]
	      If  a  pipeline is given,	the times used to execute the pipeline
	      are reported.  If	no pipeline is given, then the user and	system
	      time  used  by the shell itself, and all the commands it has run
	      since it was started, are	reported.  The times reported are  the
	      real time	(elapsed time from start to finish), the user CPU time
	      (time spent running in user mode)	and the	system CPU time	 (time
	      spent  running  in kernel	mode).	Times are reported to standard
	      error; the format	of the output is:
		  0.00s	real	 0.00s user	0.00s system
	      unless the -p option is given (only possible if  pipeline	 is  a
	      simple command), in which	case the output	is slightly longer:
		  real	 0.00
		  user	 0.00
		  sys	 0.00
	      (the  number of digits after the decimal may vary	from system to
	      system).	Note that simple redirections of standard error	do not
	      effect the output	of the time command:
				   time	sleep 1	2> afile
				 { time	sleep 1; } 2> afile
	      times for	the first command do not go to afile, but those	of the
	      second command do.

       times  Print the	accumulated user and system times used	by  the	 shell
	      and by processes which have exited that the shell	started.

       trap [handler signal ...]
	      Sets  trap handler that is to be executed	when any of the	speci-
	      fied signals are received.  Handler is either a null string, in-
	      dicating	the signals are	to be ignored, a minus (-), indicating
	      that the default action is to be taken for the signals (see sig-
	      nal(3)),	or  a string containing	shell commands to be evaluated
	      and executed at the first	opportunity (i.e.,  when  the  current
	      command completes, or before printing the	next PS1 prompt) after
	      receipt of one of	the signals.  Signal is	the name of  a	signal
	      (e.g.,  PIPE  or	ALRM) or the number of the signal (see kill -l
	      command above).  There are two special signals: EXIT (also known
	      as  0),  which  is executed when the shell is about to exit, and
	      ERR which	is executed after an error occurs (an error  is	 some-
	      thing  that  would  cause	the shell to exit if the -e or errexit
	      option were set -- see set command above).   EXIT	 handlers  are
	      executed	in the environment of the last executed	command.  Note
	      that for non-interactive shells,	the  trap  handler  cannot  be
	      changed for signals that were ignored when the shell started.

	      With no arguments, trap lists, as	a series of trap commands, the
	      current state of the traps that have been	set  since  the	 shell
	      started.	Note that the output of	trap can not be	usefully piped
	      to another process (an artifact  of  the	fact  that  traps  are
	      cleared when subprocesses	are created).

	      The original Korn	shell's	DEBUG trap and the handling of ERR and
	      EXIT traps in functions are not yet implemented.

       true   A	command	that exits with	a zero value.

       typeset [[+-Ulprtux] [-L[n]]  [-R[n]]  [-Z[n]]  [-i[n]]	|  -f  [-tux]]
       [name[=value] ...]
	      Display  or  set	parameter attributes.  With no name arguments,
	      parameter	attributes are displayed: if no	options	arg used,  the
	      current attributes of all	parameters are printed as typeset com-
	      mands; if	an option is given (or - with no  option  letter)  all
	      parameters  and  their  values with the specified	attributes are
	      printed; if options are introduced with +, parameter values  are
	      not printed.

	      If name arguments	are given, the attributes of the named parame-
	      ters are set (-) or cleared (+).	Values for parameters may  op-
	      tionally	be  specified.	 If typeset is used inside a function,
	      any newly	created	parameters are local to	the function.

	      When -f is used, typeset operates	on  the	 attributes  of	 func-
	      tions.  As with parameters, if no	names are given, functions are
	      listed with their	values (i.e., definitions) unless options  are
	      introduced with +, in which case only the	function names are re-

	       -Ln		 Left justify attribute: n specifies the field
				 width.	  If  n	 is not	specified, the current
				 width of a parameter (or  the	width  of  its
				 first assigned	value) is used.	 Leading white
				 space (and zeros, if used with	the -Z option)
				 is stripped.  If necessary, values are	either
				 truncated or space padded to  fit  the	 field
	       -Rn		 Right	justify	 attribute:  n	specifies  the
				 field width.  If n is not specified, the cur-
				 rent  width  of  a parameter (or the width of
				 its first assigned value) is used.   Trailing
				 white space are stripped.  If necessary, val-
				 ues are either	stripped of leading characters
				 or  space  padded  to make them fit the field
	       -Zn		 Zero fill attribute: if not combined with -L,
				 this  is  the same as -R, except zero padding
				 is used instead of space padding.

	       -in		 integer attribute: n specifies	 the  base  to
				 use when displaying the integer (if not spec-
				 ified,	the base given in the first assignment
				 is used).  Parameters with this attribute may
				 be assigned values containing arithmetic  ex-
	       -U		 unsigned   integer  attribute:	 integers  are
				 printed as unsigned values (only useful  when
				 combined with the -i option).	This option is
				 not in	the original Korn shell.
	       -f		 Function mode:	display	or set	functions  and
				 their attributes, instead of parameters.
	       -l		 Lower case attribute: all  upper case charac-
				 ters in values	are converted to  lower	 case.
				 (In  the  original Korn shell,	this parameter
				 meant `long integer' when used	 with  the  -i
	       -p		 Print	complete  typeset commands that	can be
				 used to re-create the attributes (but not the
				 values)  of  parameters.  This	is the default
				 action	(option	exists for  ksh93  compatibil-
	       -r		 Readonly  attribute: parameters with the this
				 attribute may not be assigned	to  or	unset.
				 Once  this  attribute	is  set, it can	not be
				 turned	off.
	       -t		 Tag attribute:	has no meaning to  the	shell;
				 provided for application use.

				 For  functions,  -t  is  the trace attribute.
				 When functions	with the trace	attribute  are
				 executed,  the	 xtrace	 (-x)  shell option is
				 temporarily turned on.
	       -u		 Upper case attribute: all lower case  charac-
				 ters  in  values are converted	to upper case.
				 (In the original Korn shell,  this  parameter
				 meant	`unsigned  integer' when used with the
				 -i option, which  meant  upper	 case  letters
				 would	never  be  used	for bases greater than
				 10.  See the -U option).

				 For functions,	-u is the undefined attribute.
				 See  Functions	 above for the implications of
	       -x		 Export	attribute: parameters  (or  functions)
				 are placed in the environment of any executed
				 commands.  Exported functions are not	imple-
				 mented	yet.

       ulimit [-abcdfHlmnpsStvw] [value]
	      Display or set process limits.  If no options are	used, the file
	      size limit (-f) is assumed.  value, if specified,	may be	either
	      be  an  arithmetic expression or the word	unlimited.  The	limits
	      affect the shell and any processes created by the	shell after  a
	      limit  is	 imposed.  Note	that some systems may not allow	limits
	      to be increased once they	are set.  Also note that the types  of
	      limits  available	 are system dependent -	some systems have only
	      the -f limit.

	      -a     Displays all limits; unless -H is used, soft  limits  are

	      -H     Set  the hard limit only (default is to set both hard and
		     soft limits).

	      -S     Set the soft limit	only (default is to set	both hard  and
		     soft limits).

	      -b     Impose a size limit of n bytes on the size	of socket buf-

	      -c     Impose a size limit of n  blocks  on  the	size  of  core

	      -d     Impose  a	size limit of n	kbytes on the size of the data

	      -f     Impose a size limit of n blocks on	files written  by  the
		     shell  and	 its child processes (files of any size	may be

	      -l     Impose a limit of	n  kbytes  on  the  amount  of	locked
		     (wired) physical memory.

	      -m     Impose a limit of n kbytes	on the amount of physical mem-
		     ory used.

	      -n     Impose a limit of n file descriptors that can be open  at

	      -p     Impose a limit of n processes that	can be run by the user
		     at	any one	time.

	      -s     Impose a size limit of n kbytes on	the size of the	 stack

	      -t     Impose  a	time limit of n	CPU seconds to be used by each

	      -v     Impose a limit of n kbytes	on the amount of virtual  mem-
		     ory  used;	 on some systems this is the maximum allowable
		     virtual address (in bytes,	not kbytes).

	      -w     Impose a limit of n kbytes	on the amount  of  swap	 space

	      As far as	ulimit is concerned, a block is	512 bytes.

       umask [-S] [mask]
	      Display  or set the file permission creation mask, or umask (see
	      umask(2)).  If the -S option is used, the	mask displayed or  set
	      is symbolic, otherwise it	is an octal number.

	      Symbolic masks are like those used by chmod(1):
	      in which the first group of characters is	the who	part, the sec-
	      ond group	is the op part,	and the	last group is the  perm	 part.
	      The  who	part  specifies	which part of the umask	is to be modi-
	      fied.  The letters mean:

		     u	    the	user permissions

		     g	    the	group permissions

		     o	    the	other permissions (non-user, non-group)

		     a	    all	permissions (user, group and other)

	      The op part indicates how	the who	permissions are	 to  be	 modi-

		     =	    set

		     +	    added to

		     -	    removed from

	      The  perm	 part specifies	which permissions are to be set, added
	      or removed:

		     r	    read permission

		     w	    write permission

		     x	    execute permission

	      When symbolic masks are used, they describe what permissions may
	      be  made available (as opposed to	octal masks in which a set bit
	      means  the  corresponding	 bit  is  to  be  cleared).   Example:
	      `ug=rwx,o='  sets	 the  mask  so	files  will  not  be readable,
	      writable or executable by	`others', and is equivalent  (on  most
	      systems) to the octal mask `07'.

       unalias [-adt] [name1 ...]
	      The  aliases  for	the given names	are removed.  If the -a	option
	      is used, all aliases are removed.	 If the	-t or -d  options  are
	      used, the	indicated operations are carried out on	tracked	or di-
	      rectory aliases, respectively.

       unset [-fv] parameter ...
	      Unset the	named parameters (-v, the default) or functions	 (-f).
	      The  exit	 status	 is non-zero if	any of the parameters were al-
	      ready unset, zero	otherwise.

       wait [job]
	      Wait for the specified job(s) to finish.	 The  exit  status  of
	      wait  is	that  of  the  last  specified job: if the last	job is
	      killed by	a signal, the exit status is 128 + the number  of  the
	      signal  (see  kill  -l exit-status above); if the	last specified
	      job can't	be found (because it never  existed,  or  had  already
	      finished),  the exit status of wait is 127.  See Job Control be-
	      low for the format of job.  Wait will return  if	a  signal  for
	      which  a trap has	been set is received, or if a HUP, INT or QUIT
	      signal is	received.

	      If no jobs are specified,	wait waits for all  currently  running
	      jobs  (if	 any)  to finish and exits with	a zero status.	If job
	      monitoring is enabled, the completion status of jobs is  printed
	      (this is not the case when jobs are explicitly specified).

       whence [-pv] [name ...]
	      For  each	 name,	the  type of command is	listed (reserved word,
	      built-in,	alias, function, tracked alias or executable).	If the
	      -p option	is used, a path	search done even if name is a reserved
	      word, alias, etc.	 Without the -v	option,	whence is  similar  to
	      command -v except	that whence will find reserved words and won't
	      print aliases as alias commands; with the	-v option,  whence  is
	      the  same	 as  command  -V.  Note	that for whence, the -p	option
	      does not affect the search path used, as it  does	 for  command.
	      If the type of one or more of the	names could not	be determined,
	      the exit status is non-zero.

   Job Control
       Job control refers to the shell's ability to monitor and	control	 jobs,
       which  are  processes  or  groups  of processes created for commands or
       pipelines.  At a	minimum, the shell keeps track of the  status  of  the
       background  (i.e., asynchronous)	jobs that currently exist; this	infor-
       mation can be displayed using the jobs  command.	  If  job  control  is
       fully  enabled  (using set -m or	set -o monitor), as it is for interac-
       tive shells, the	processes of a job are placed  in  their  own  process
       group,  foreground  jobs	can be stopped by typing the suspend character
       from the	terminal (normally ^Z),	jobs can be restarted  in  either  the
       foreground  or  background, using the fg	and bg commands, respectively,
       and the state of	the terminal is	saved or restored  when	 a  foreground
       job is stopped or restarted, respectively.

       Note  that only commands	that create processes (e.g., asynchronous com-
       mands, subshell commands, and non-built-in, non-function	commands)  can
       be stopped; commands like read cannot be.

       When  a	job  is	created, it is assigned	a job-number.  For interactive
       shells, this number is printed inside [..], followed by the process-ids
       of the processes	in the job when	an asynchronous	command	is run.	 A job
       may be referred to in bg, fg, jobs, kill	and wait  commands  either  by
       the  process  id	of the last process in the command pipeline (as	stored
       in the $! parameter) or by prefixing the	job-number with	a percent sign
       (%).  Other percent sequences can also be used to refer to jobs:

	%+			 The  most  recently stopped job, or, if there
				 are no	stopped	jobs, the oldest running job.
	%%, %			 Same as %+.
	%-			 The job that would be	the  %+	 job,  if  the
				 later did not exist.
	%n			 The job with job-number n.
	%?string		 The  job containing the string	string (an er-
				 ror occurs if multiple	jobs are matched).
	%string			 The job starting with string string (an error
				 occurs	if multiple jobs are matched).

       When a job changes state	(e.g., a background job	finishes or foreground
       job is stopped),	the shell prints the following status information:
	      [number] flag status command

	      is the job-number	of the job.

	flag  is + or -	if the job is the %+ or	%- job,	respectively, or space
	      if it is neither.

	      indicates	the current state of the job and can be

		     the  job has neither stopped or exited (note that running
		     does not necessarily  mean	 consuming  CPU	 time  --  the
		     process could be blocked waiting for some event).

	      Done [(number)]
		     the  job  exited.	 number	is the exit status of the job,
		     which is omitted if the status is zero.

	      Stopped [(signal)]
		     the job was stopped by the	indicated signal (if no	signal
		     is	given, the job was stopped by SIGTSTP).

	      signal-description [(core	dumped)]
		     the  job  was  killed  by	a  signal (e.g., Memory	fault,
		     Hangup, etc. -- use kill -l for a list of signal descrip-
		     tions).   The (core dumped) message indicates the process
		     created a core file.

	      is the command that created the process.	If there are  multiple
	      processes	in the job, then each process will have	a line showing
	      its command and possibly its status, if it is different from the
	      status of	the previous process.

       When  an	 attempt is made to exit the shell while there are jobs	in the
       stopped state, the shell	warns the user that there are stopped jobs and
       does  not  exit.	  If  another  attempt is immediately made to exit the
       shell, the stopped jobs are sent	a HUP  signal  and  the	 shell	exits.
       Similarly,  if  the  nohup option is not	set and	there are running jobs
       when an attempt is made to exit a login shell, the shell	warns the user
       and  does not exit.  If another attempt is immediately made to exit the
       shell, the running jobs are sent	a HUP signal and the shell exits.

   Interactive Input Line Editing
       The shell supports three	modes of reading command lines from a  tty  in
       an  interactive	session.   Which  is  used is controlled by the	emacs,
       gmacs and vi set	options	(at most one of	these can be set at once).  If
       none  of	 these	options	is enabled, the	shell simply reads lines using
       the normal tty driver.  If the emacs or gmacs option is set, the	 shell
       allows  emacs  like editing of the command; similarly, if the vi	option
       is set, the shell allows	vi like	editing	of the command.	  These	 modes
       are described in	detail in the following	sections.

       In  these editing modes,	if a line is longer that the screen width (see
       COLUMNS parameter), a >,	+ or < character is displayed in the last col-
       umn  indicating that there are more characters after, before and	after,
       or before the current position, respectively.   The  line  is  scrolled
       horizontally as necessary.

   Emacs Editing Mode
       When  the  emacs	 option	 is set, interactive input line	editing	is en-
       abled.  Warning:	This mode is slightly different	from the emacs mode in
       the  original Korn shell	and the	8th bit	is stripped in emacs mode.  In
       this mode various editing commands (typically bound to one or more con-
       trol  characters)  cause	 immediate  actions without waiting for	a new-
       line.  Several editing commands are bound to particular control charac-
       ters when the shell is invoked; these bindings can be changed using the
       following commands:

       bind   The current bindings are listed.

       bind string=[editing-command]
	      The specified editing command is	bound  to  the	given  string,
	      which  should consist of a control character (which may be writ-
	      ten using	caret notation ^X), optionally preceded	by one of  the
	      two  prefix  characters.	 Future	input of the string will cause
	      the editing command to be	immediately invoked.   Note  that  al-
	      though  only two prefix characters (usually ESC and ^X) are sup-
	      ported, some multi-character sequences can  be  supported.   The
	      following	 binds	the  arrow  keys on an ANSI terminal, or xterm
	      (these are in the	default	bindings).  Of course some escape  se-
	      quences won't work out quite this	nicely:

	      bind '^[['=prefix-2
	      bind '^XA'=up-history
	      bind '^XB'=down-history
	      bind '^XC'=forward-char
	      bind '^XD'=backward-char

       bind -l
	      Lists the	names of the functions to which	keys may be bound.

       bind -m string=[substitute]
	      The  specified  input  string will afterwards be immediately re-
	      placed by	the given substitute string, which may contain editing

       The  following  is a list of editing commands available.	 Each descrip-
       tion starts with	the name of the	command, a n, if the  command  can  be
       prefixed	 with a	count, and any keys the	command	is bound to by default
       (written	using caret notation, e.g., ASCII ESC character	is written  as
       ^[).   A	 count prefix for a command is entered using the sequence ^[n,
       where n is a sequence of	1 or more digits; unless otherwise  specified,
       if  a  count  is	 omitted, it defaults to 1.  Note that editing command
       names are used only with	the bind command.  Furthermore,	 many  editing
       commands	 are  useful only on terminals with a visible cursor.  The de-
       fault bindings were chosen to resemble corresponding  EMACS  key	 bind-
       ings.   The  users tty characters (e.g.,	ERASE) are bound to reasonable
       substitutes and override	the default bindings.

       abort ^G
	      Useful as	a response to a	request	for a  search-history  pattern
	      in order to abort	the search.

       auto-insert n
	      Simply  causes  the  character to	appear as literal input.  Most
	      ordinary characters are bound to this.

       backward-char  n	^B
	      Moves the	cursor backward	n characters.

       backward-word  n	^[B
	      Moves the	cursor backward	to the beginning of a word; words con-
	      sist of alphanumerics, underscore	(_) and	dollar ($).

       beginning-of-history ^[<
	      Moves to the beginning of	the history.

       beginning-of-line ^A
	      Moves the	cursor to the beginning	of the edited input line.

       capitalize-word n ^[c, ^[C
	      Uppercase	 the  first character in the next n words, leaving the
	      cursor past the end of the last word.  If	the current line  does
	      not  begin  with a comment character, one	is added at the	begin-
	      ning of the line and the line is entered (as if return had  been
	      pressed),	 otherwise the existing	comment	characters are removed
	      and the cursor is	placed at the beginning	of the line.

       complete	^[^[

       complete	^I
	      Automatically completes as much as is unique of the command name
	      or the file name containing the cursor.  If the entire remaining
	      command or file name is unique a space is	printed	after its com-
	      pletion,	unless	it  is a directory name	in which case /	is ap-
	      pended.  If there	is no command or file name  with  the  current
	      partial  word as its prefix, a bell character is output (usually
	      causing a	audio beep).

       complete-command	^X^[
	      Automatically completes as much as is unique of the command name
	      having  the  partial  word up to the cursor as its prefix, as in
	      the complete command described above.

       complete-file ^[^X
	      Automatically completes as much as is unique of  the  file  name
	      having  the  partial  word up to the cursor as its prefix, as in
	      the complete command described above.

       complete-list ^[=
	      List the possible	completions for	the current word.

       delete-char-backward n ERASE, ^?, ^H
	      Deletes n	characters before the cursor.

       delete-char-forward n
	      Deletes n	characters after the cursor.

       delete-word-backward n ^[ERASE, ^[^?, ^[^H, ^[h
	      Deletes n	words before the cursor.

       delete-word-forward n ^[d
	      Deletes characters after the cursor up to	the end	of n words.

       down-history n ^N
	      Scrolls the history buffer forward n lines (later).  Each	 input
	      line  originally starts just after the last entry	in the history
	      buffer, so down-history is not useful until  either  search-his-
	      tory or up-history has been performed.

       downcase-word n ^[L, ^[l
	      Lowercases the next n words.

       end-of-history ^[>
	      Moves to the end of the history.

       end-of-line ^E
	      Moves the	cursor to the end of the input line.

       eot ^_ Acts  as	an end-of-file;	this is	useful because edit-mode input
	      disables normal terminal input canonicalization.

       eot-or-delete n ^D
	      Acts as eot if alone on a	line; otherwise	acts  as  delete-char-

       error  Error (ring the bell).

       exchange-point-and-mark ^X^X
	      Places  the cursor where the mark	is, and	sets the mark to where
	      the cursor was.

       expand-file ^[*
	      Appends a	* to the current word and replaces the word  with  the
	      result  of  performing  file  globbing on	the word.  If no files
	      match the	pattern, the bell is rung.

       forward-char n ^F
	      Moves the	cursor forward n characters.

       forward-word n ^[f
	      Moves the	cursor forward to the end of the nth word.

       goto-history n ^[g
	      Goes to history number n.

       kill-line KILL
	      Deletes the entire input line.

       kill-region ^W
	      Deletes the input	between	the cursor and the mark.

       kill-to-eol n ^K
	      Deletes the input	from the cursor	to the end of the line if n is
	      not  specified,  otherwise deletes characters between the	cursor
	      and column n.

       list ^[?
	      Prints a sorted, columnated list of command names	or file	 names
	      (if  any)	that can complete the partial word containing the cur-
	      sor.  Directory names have / appended to them.

       list-command ^X?
	      Prints a sorted, columnated list of command names	(if any)  that
	      can complete the partial word containing the cursor.

       list-file ^X^Y
	      Prints a sorted, columnated list of file names (if any) that can
	      complete the partial word	containing the cursor.	File type  in-
	      dicators are appended as described under list above.

       newline ^J, ^M
	      Causes the current input line to be processed by the shell.  The
	      current cursor position may be anywhere on the line.

       newline-and-next	^O
	      Causes the current input line to be processed by the shell,  and
	      the  next	 line  from history becomes the	current	line.  This is
	      only useful after	an up-history or search-history.

       no-op QUIT
	      This does	nothing.

       prefix-1	^[
	      Introduces a 2-character command sequence.

       prefix-2	^X

       prefix-2	^[[
	      Introduces a 2-character command sequence.

       prev-hist-word n	^[., ^[_
	      The last (nth) word of the previous command is inserted  at  the

       quote ^^
	      The  following  character	 is  taken literally rather than as an
	      editing command.

       redraw ^L
	      Reprints the prompt string and the current input line.

       search-character-backward n ^[^]
	      Search backward in the current line for the  nth	occurrence  of
	      the next character typed.

       search-character-forward	n ^]
	      Search forward in	the current line for the nth occurrence	of the
	      next character typed.

       search-history ^R
	      Enter incremental	search mode.  The  internal  history  list  is
	      searched	backwards for commands matching	the input.  An initial
	      ^	in the search string anchors the search.  The abort  key  will
	      leave  search mode.  Other commands will be executed after leav-
	      ing search mode.	Successive  search-history  commands  continue
	      searching	 backward  to the next previous	occurrence of the pat-
	      tern.  The history buffer	retains	only a finite number of	lines;
	      the oldest are discarded as necessary.

       set-mark-command	^[<space>
	      Set the mark at the cursor position.

       stuff  On  systems  supporting it, pushes the bound character back onto
	      the terminal input where it may receive  special	processing  by
	      the terminal handler.  This is useful for	the BRL	^T mini-systat
	      feature, for example.

	      Acts like	stuff, then aborts input the same as an	interrupt.

       transpose-chars ^T
	      If at the	end of line, or	if the gmacs option is set,  this  ex-
	      changes the two previous characters; otherwise, it exchanges the
	      previous and current characters and moves	the cursor one charac-
	      ter to the right.

       up-history n ^P
	      Scrolls the history buffer backward n lines (earlier).

       upcase-word n ^[U, ^[u
	      Uppercases the next n words.

       version ^V
	      Display the version of ksh.  The current edit buffer is restored
	      as soon as any key is pressed (the key is	then processed,	unless
	      it is a space).

       yank ^Y
	      Inserts the most recently	killed text string at the current cur-
	      sor position.

       yank-pop	^[y
	      Immediately after	a yank,	replaces the inserted text string with
	      the next previous	killed text string.

   Vi Editing Mode
       The  vi	command	 line editor in	ksh has	basically the same commands as
       the vi editor (see vi(1)), with the following exceptions:

	 o    you start	out in insert mode,

	 o    there are	file name and command completion commands  (=,	\,  *,
	      ^X, ^E, ^F and, optionally, <tab>),

	 o    the  _ command is	different (in ksh it is	the last argument com-
	      mand, in vi it goes to the start of the current line),

	 o    the / and	G commands move	in the opposite	 direction  as	the  j

	 o    and  commands which don't	make sense in a	single line editor are
	      not available (e.g., screen movement commands,  ex  :  commands,

       Note  that  the	^X stands for control-X; also <esc>, <space> and <tab>
       are used	for escape, space and tab, respectively	(no kidding).

       Like vi,	there are two modes: insert mode and command mode.  In	insert
       mode,  most characters are simply put in	the buffer at the current cur-
       sor position as they are	typed, however,	some  characters  are  treated
       specially.  In particular, the following	characters are taken from cur-
       rent tty	settings (see stty(1)) and have	their  usual  meaning  (normal
       values  are  in	parentheses):  kill (^U), erase	(^?), werase (^W), eof
       (^D), intr (^C) and quit	(^\).  In addition to the above, the following
       characters are also treated specially in	insert mode:

	^H			 erases	previous character
	^V			 literal next: the next	character typed	is not
				 treated specially (can	be used	to insert  the
				 characters being described here)
	^J ^M			 end of	line: the current line is read,	parsed
				 and executed by the shell
	<esc>			 puts the editor in command mode (see below)
	^E			 command and file name enumeration (see	below)
	^F			 command and file name completion (see below).
				 If  used twice	in a row, the list of possible
				 completions is	displayed;  if	used  a	 third
				 time, the completion is undone.
	^X			 command and file name expansion (see below)
	<tab>			 optional  file	 name  and  command completion
				 (see ^F above), enabled with set  -o  vi-tab-

       In  command  mode, each character is interpreted	as a command.  Charac-
       ters that don't correspond to commands,	are  illegal  combinations  of
       commands	or are commands	that can't be carried out all cause beeps.  In
       the following command descriptions, a n indicates the  command  may  be
       prefixed	 by a number (e.g., 10l	moves right 10 characters); if no num-
       ber prefix is used, n is	assumed	to be 1	 unless	 otherwise  specified.
       The  term  `current position' refers to the position between the	cursor
       and the character preceding the cursor.	A `word' is a sequence of let-
       ters,  digits  and  underscore  characters or a sequence	of non-letter,
       non-digit, non-underscore,  non-white-space  characters	(e.g.,	ab2*&^
       contains	 two  words) and a `big-word' is a sequence of non-white-space

       Special ksh vi commands
	      The following commands are not in, or are	 different  from,  the
	      normal vi	file editor:

	      n_     insert a space followed by	the nth	big-word from the last
		     command in	the history at the current position and	 enter
		     insert  mode; if n	is not specified, the last word	is in-

	      #	     insert the	comment	character (#) at the start of the cur-
		     rent line and return the line to the shell	(equivalent to

	      ng     like G, except if n is not	specified, it goes to the most
		     recent remembered line.

	      nv     edit  line	 n using the vi	editor;	if n is	not specified,
		     the current line is edited.  The actual command  executed
		     is	`fc -e ${VISUAL:-${EDITOR:-vi}}	n'.

	      *	and ^X
		     command  or file name expansion is	applied	to the current
		     big-word (with an appended	*, if  the  word  contains  no
		     file  globing characters) - the big-word is replaced with
		     the resulting words.  If  the  current  big-word  is  the
		     first  on the line	(or follows one	of the following char-
		     acters: ;,	|, &, (, )) and	does not contain a  slash  (/)
		     then  command  expansion is done, otherwise file name ex-
		     pansion is	done.  Command expansion will match  the  big-
		     word against all aliases, functions and built-in commands
		     as	well as	any executable files found  by	searching  the
		     directories  in  the PATH parameter.  File	name expansion
		     matches the big-word against the files in the current di-
		     rectory.  After expansion,	the cursor is placed just past
		     the last word and the editor is in	insert mode.

	      n\, n^F, n<tab> and n<esc>
		     command/file name completion: replace  the	 current  big-
		     word  with	 the  longest unique match obtained after per-
		     forming command/file name expansion.  <tab> is only  rec-
		     ognized  if the vi-tabcomplete option is set, while <esc>
		     is	only recognized	if the vi-esccomplete  option  is  set
		     (see  set	-o).  If n is specified, the nth possible com-
		     pletion is	selected (as reported by the command/file name
		     enumeration command).

	      =	and ^E
		     command/file  name	 enumeration: list all the commands or
		     files that	match the current big-word.

	      ^V     display the version of pdksh; it is displayed  until  an-
		     other key is pressed (this	key is ignored).

	      @c     macro  expansion: execute the commands found in the alias

       Intra-line movement commands

	      nh and n^H
		     move left n characters.

	      nl and n<space>
		     move right	n characters.

	      0	     move to column 0.

	      ^	     move to the first non white-space character.

	      n|     move to column n.

	      $	     move to the last character.

	      nb     move back n words.

	      nB     move back n big-words.

	      ne     move forward to the end the word, n times.

	      nE     move forward to the end the big-word, n times.

	      nw     move forward n words.

	      nW     move forward n big-words.

	      %	     find match: the editor  looks  forward  for  the  nearest
		     parenthesis,  bracket  or brace and then moves the	to the
		     matching parenthesis, bracket or brace.

	      nfc    move forward to the nth occurrence	of the character c.

	      nFc    move backward to the nth occurrence of the	character c.

	      ntc    move forward to just before the  nth  occurrence  of  the
		     character c.

	      nTc    move  backward  to	 just before the nth occurrence	of the
		     character c.

	      n;     repeats the last f, F, t or T command.

	      n,     repeats the last f, F, t or T command, but	moves  in  the
		     opposite direction.

       Inter-line movement commands

	      nj and n+	and n^N
		     move to the nth next line in the history.

	      nk and n-	and n^P
		     move to the nth previous line in the history.

	      nG     move to line n in the history; if n is not	specified, the
		     number first remembered line is used.

	      ng     like G, except if n is not	specified, it goes to the most
		     recent remembered line.

		     search backward through the history for the nth line con-
		     taining string; if	string starts with ^, the remainder of
		     the  string  must appear at the start of the history line
		     for it to match.

		     same as /,	except it searches forward  through  the  his-

	      nn     search  for the nth occurrence of the last	search string;
		     the direction of the search  is  the  same	 as  the  last

	      nN     search  for the nth occurrence of the last	search string;
		     the direction of the search is the	opposite of  the  last

       Edit commands

	      na     append text n times: goes into insert mode	just after the
		     current position.	The append is only replicated if  com-
		     mand mode is re-entered (i.e., <esc> is used).

	      nA     same as a,	except it appends at the end of	the line.

	      ni     insert text n times: goes into insert mode	at the current
		     position.	The insertion is only  replicated  if  command
		     mode is re-entered	(i.e., <esc> is	used).

	      nI     same  as  i, except the insertion is done just before the
		     first non-blank character.

	      ns     substitute	the next n characters (i.e., delete the	 char-
		     acters and	go into	insert mode).

	      S	     substitute	whole line: all	characters from	the first non-
		     blank character to	the end	of line	are deleted and	insert
		     mode is entered.

		     change  from the current position to the position result-
		     ing from n	move-cmds (i.e., delete	the  indicated	region
		     and  go  into  insert  mode);  if move-cmd	is c, the line
		     starting from the first non-blank character is changed.

	      C	     change from the current position to the end of  the  line
		     (i.e.,  delete  to	the end	of the line and	go into	insert

	      nx     delete the	next n characters.

	      nX     delete the	previous n characters.

	      D	     delete to the end of the line.

		     delete from the current position to the position  result-
		     ing from n	move-cmds; move-cmd is a movement command (see
		     above) or d, in which case	the current line is deleted.

	      nrc    replace the next n	characters with	the character c.

	      nR     replace: enter insert mode	but overwrite existing charac-
		     ters  instead  of	inserting  before existing characters.
		     The replacement is	repeated n times.

	      n~     change the	case of	the next n characters.

		     yank from the current position to the position  resulting
		     from  n move-cmds into the	yank buffer; if	move-cmd is y,
		     the whole line is yanked.

	      Y	     yank from the current position to the end of the line.

	      np     paste the contents	of the yank buffer just	after the cur-
		     rent position, n times.

	      nP     same as p,	except the buffer is pasted at the current po-

       Miscellaneous vi	commands

	      ^J and ^M
		     the current line is read,	parsed	and  executed  by  the

	      ^L and ^R
		     redraw the	current	line.

	      n.     redo the last edit	command	n times.

	      u	     undo the last edit	command.

	      U	     undo all changes that have	been made to the current line.

	      intr and quit
		     the interrupt and quit terminal characters	cause the cur-
		     rent line to be deleted and a new prompt to be printed.


       Any bugs	in pdksh should	be reported to   Please  in-
       clude  the  version of pdksh (echo $KSH_VERSION shows it), the machine,
       operating system	and compiler you are using and a description of	how to
       repeat  the  bug	 (a  small  shell  script that demonstrates the	bug is
       best).  The following, if relevant (if you are not sure,	include	them),
       can also	helpful: options you are using (both options.h options and set
       -o options) and a copy of your config.h (the file generated by the con-
       figure	script).    New	  versions  of	pdksh  can  be	obtained  from

       BTW, the	most frequently	reported bug is
	       echo hi | read a; echo $a   # Does not print hi
       I'm aware of this and there is no need to report	it.

       This page documents version
			    @(#)PD KSH v5.2.14 99/07/13.2
       of the public domain korn shell.

       This shell is based on the public domain	7th edition Bourne shell clone
       by  Charles  Forsyth  and  parts	of the BRL shell by Doug A. Gwyn, Doug
       Kingston, Ron Natalie, Arnold Robbins, Lou  Salkind  and	 others.   The
       first  release  of  pdksh  was created by Eric Gisin, and it was	subse-
       quently maintained by John R.  MacMillan	 (chance!,  and
       Simon  J.  Gerraty  (   The	current	 maintainer is
       Michael Rendell (   The  CONTRIBUTORS	 file  in  the
       source  distribution  contains a	more complete list of people and their
       part in the shell's development.

       awk(1), sh(1), csh(1), ed(1), getconf(1), getopt(1),  sed(1),  stty(1),
       vi(1),  dup(2),	execve(2),  getgid(2),	getuid(2),  open(2),  pipe(2),
       wait(2),	getopt(3), rand(3), signal(3), system(3), environ(7)

       The KornShell Command and Programming Language, Morris Bolsky and David
       Korn, 1989, ISBN	0-13-516972-0.

       UNIX Shell Programming, Stephen G. Kochan, Patrick H. Wood, Hayden.

       IEEE  Standard  for  information	Technology - Portable Operating	System
       Interface (POSIX) - Part	2: Shell and Utilities,	IEEE Inc,  1993,  ISBN

				August 19, 1996				KSH(1)


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