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KSH(1)				 User commands				KSH(1)

NAME
       ksh - Public domain Korn	shell

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

DESCRIPTION
       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 and	$HOME/.profile 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 ENV  parameter  is  not
       set  (and  not  null) and pdksh was compiled with the DEFAULT_ENV macro
       defined,	the file named in that macro is	included (after	the above men-
       tioned 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-
       low).

       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-
       ple,
	      {	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
	      zero.

       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
	      zero.

       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
	      section.

       (( 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	]]
		     succeeds).
		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-
		     tively.
		o    The single	argument form of test, which tests if the  ar-
		     gument has	non-zero length, is not	valid -	explicit oper-
		     ators must	be always be used, e.g., instead of
					      [	str ]
		     use
					   [[ -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
       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: see POSIX Mode below for a	special	rule  regarding	 sequences  of
       the form	"...`...\"...`..".

   Aliases
       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'
	      local='typeset'
	      login='exec login'
	      newgrp='exec newgrp'
	      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.

   Substitution
       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
       soon.

       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
       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 indicies 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-
       curs.

       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(5))  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:

       ${name:-word}
	      if name is set and not null, it is substituted,  otherwise  word
	      is substituted.

       ${name:+word}
	      if  name	is  set	 and  not null,	word is	substituted, otherwise
	      nothing is substituted.

       ${name:=word}
	      if name is set and not null, it is substituted, otherwise	it  is
	      assigned word and	the resulting value of name is substituted.

       ${name:?word}
	      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:

       ${#name}
	      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
	      value.

       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
	      null).

       @      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 loosing
	      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.

       COLUMNS
	      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.

       EXECSHELL
	      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.

       HISTFILE
	      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.

       HISTSIZE
	      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-
	      tails.
	      Note:  this  parameter is	not imported from the environment when
	      the shell	is started.

       KSH_VERSION
	      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.

       MAILCHECK
	      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).

       MAILPATH
	      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.

       POSIXLY_CORRECT
	      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.

       SECONDS
	      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,
	      respectively.

   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
	      prefix{str1,...,strN}suffix
       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-
	      ets.

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

       +(pattern| ... |pattern)
	      matches  any string of characters	that matches one or more occu-
	      rances  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
	      reading.

       <> 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 -
		     negation.

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

	      ~	     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-
		     ter.

	      ++     similar to	++, except the paramter	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.

	      !=     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
		     _arg3_.

   Co-Processes
       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-processs	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
       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
       status.

       Functions  defined  with	the function reserved word are treated differ-
       ently in	the following ways from	functions defined with	the  ()	 nota-
       tion:
	 o    the  $0  parameter  is  set to the name of the function (Bourne-
	      style functions leave $0 untouched).
	 o    parameter	assignments preceeding 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-
       sirable).

       The following is	a list of things that are affected by the state	of the
       posix option:
	 o    \"  inside  double  quoted  `..` command substitutions: in posix
	      mode, the	\" is interpreted when the command is interpreted;  in
	      non-posix	 mode,	the  backslash	is stripped before the command
	      substitution is interpreted.  For	example, echo "`echo  \"hi\"`"
	      produces `"hi"' in posix mode, `hi' in non-posix mode.  To avoid
	      problems,	use the	$(...)	form of	command	substitution.
	 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  pre-
       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
       them.

       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
       command.

       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 [-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-
	      scription.

       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.	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  di-
	      rectory $HOME is used.  If dir is	-, the previous	working	direc-
	      tory 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
	      directory	 tree.	 The  PWD and OLDPWD parameters	are updated to
	      reflect 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	be found, (i.e., the path search fails), noth-
	      ing is printed and command exits with a non-zero status.	The -V
	      option 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-
	      nized.

	      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 which 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
	      process.

	      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-
	      rameter.

       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) argument that does not start with	a -, or	when a --  ar-
	      gument is	encountered.

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

	      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
	      command.

       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
	      job.

       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
	      "expr".

       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-
	      line.

       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
						untouched.
	       -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-
						write).
	       -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-
						terns.
	       -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-
						active).

	       -p	  privileged		Set automatically if, when the
						shell  starts, the read	uid or
						gid does not match the	effec-
						tive uid or gid, respectively.
						See Shell Startup above	for  a
						description   of   what	  this
						means.
	       -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-
						tion.
			  bgnice		Background jobs	are  run  with
						lower priority.
			  braceexpand		Enable	brace  expansion (aka,
						alternation).
			  emacs			Enable BRL emacs-like  command
						line	editing	  (interactive
						shells only); see Emacs	 Edit-
						ing Mode.
			  gmacs			Enable	 gmacs-like   (Gosling
						emacs)	command	 line  editing
						(interactive   shells	only);
						currently identical  to	 emacs
						editing	 except	that transpose
						(^T)  acts  slightly   differ-
						ently.
			  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
						file.

			  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 obliveous 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
						details.
			  posix			Enable posix mode.  See	 POSIX
						Mode above.
			  vi			Enable	vi-like	 command  line
						editing	 (interactive	shells
						only).
			  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.

	      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,
	      and 1 status if false and	greater	than 1 if there	was an	error.
	      It  is  normally	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 po-
				    tential for	problems if  str
				    turns  out to be an	operator
				    (e.g., -r) - it is generally
				    better to use a test like
						  [  X"str" != X
						  ]
					   instead	 (double
					   quotes  are	used  in
					   case	  str	contains
					   spaces  or file glob-
					   ing characters).
	       -r file		    file exists	and is readable.
	       -w file		    file exists	and is writable.
	       -x file		    file  exists  and  is   exe-
				    cutable.
	       -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
				    device.
	       -b file		    file is a block special  de-
				    vice.
	       -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
				    effective user-ID.
	       -G file		    file's  group is the shell's
				    effective group-ID.
	       -h file		    file is a symbolic link.
	       -H file		    file is a context  dependent
				    directory  (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
				    options).  As a non-standard
				    extension,	 if  the  option
				    starts with	a !, the test is
				    negated;   the  test  always
				    fails if option doesn't  ex-
				    ist	(thus
						  [ -o foo -o -o
						  !foo ]
					   returns true	 if  and
					   only	 if  option  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 de-
				    vice.  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
				    described 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 equal.
	       number -gt number    numbers   compare	 greater
				    than.
	       number -le number    numbers compare less than or
				    equal.
	       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
	      writable.

	      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(2 or 3)), or a string	containing shell commands to be	evalu-
	      ated and executed	at the first opportunity (i.e.,	when the  cur-
	      rent  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 something that	would cause the	shell to exit if the -e	or er-
	      rexit 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-
	      ported.

	       -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
				 width.

	       -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
				 width.
	       -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-
				 pressions.
	       -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
				 option).
	       -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  compatabil-
				 ity).
	       -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
				 this.
	       -x		 Export	attribute: parameters  (or  functions)
				 are placed in the environment of any executed
				 commands.  Exported functions are not	imple-
				 mented	yet.

       ulimit [-acdfHlmnpsStvw]	[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
		     displayed.

	      -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).

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

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

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

	      -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
		     once.

	      -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
		     area.

	      -t     Impose a time limit of n cpu seconds to be	used  by  each
		     process.

	      -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
		     used.

	      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):
		     [ugoa]{{=+-}{rwx}*}+[,...]
	      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-
	      fied:

		     =	    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
       where

	number
	      is the job-number	of the job.

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

	status
	      indicates	the current state of the job and can be

	      Running
		     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.

	command
	      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
	      commands.

       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	^[^[
	      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-
	      forward.

       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
	      cursor.

       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 occurance	of the
	      next character typed.

       search-character-forward	n ^]
	      Search forward in	the current line for the nth occurance 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.

       stuff-reset
	      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
	      command

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

       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-
				 complete

       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
       characters.

       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-
		     serted.

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

	      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
		     _c.

       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.

	      n/string
		     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.

	      n?string
		     same  as  /,  except it searches forward through the his-
		     tory.

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

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

       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.

	      ncmove-cmd
		     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
		     mode).

	      nx     delete the	next n characters.

	      nX     delete the	previous n characters.

	      D	     delete to the end of the line.

	      ndmove-cmd
		     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.

	      nymove-cmd
		     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-
		     sition.

       Miscellaneous vi	commands

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

	      ^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.

FILES
       ~/.profile
       /etc/profile
       /etc/suid_profile

BUGS
       Any  bugs  in  pdksh should be reported to pdksh@cs.mun.ca.  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
       ftp://ftp.cs.mun.ca/pub/pdksh/.

       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.

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

AUTHORS
       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!john@sq.sq.com), and
       Simon J.	 Gerraty  (sjg@zen.void.oz.au).	  The  current	maintainer  is
       Michael	Rendell	 (michael@cs.mun.ca).	The  CONTRIBUTORS  file	in the
       source distribution contains a more complete list of people  and	 their
       part in the shell's development.

SEE ALSO
       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(5)

       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
       1-55937-255-9.

				August 19, 1996				KSH(1)

NAME | SYNOPSIS | DESCRIPTION | FILES | BUGS | VERSION | AUTHORS | SEE ALSO

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