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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
	      arguments	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-
       option  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
       input and standard error	are attached to	a tty.	An  interactive	 shell
       has  job	control	enabled	(if available),	ignores	the INT, QUIT and TERM
       signals,	and prints prompts before  reading  input  (see	 PS1  and  PS2
       parameters).   For non-interactive shells, the trackall option is on by
       default (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
       restrictions 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
       getuid(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
       resulting 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
       error  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
       ignored,	 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); ~
       begins 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	below).

       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
       using  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
       descriptors 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
		     argument  has  non-zero  length,  is not valid - explicit
		     operators 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
		     exists 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
       expression.  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
       occurs.

       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,
       parameters are  imported	 from  the  shell's  environment  at  startup.
       Third, parameters can be	assigned values	on the command line, for exam-
       ple, `FOO=bar' sets  the	 parameter  FOO	 to  bar;  multiple  parameter
       assignments  can	be given on a single command line and they can be fol-
       lowed 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 assignment.  The fourth way of	setting	a  parameter  is  with
       the  export,  readonly  and typeset commands; see their descriptions in
       the Command Execution section.  Fifth, for and select loops set parame-
       ters as well as the getopts, read and set -A commands.  Lastly, parame-
       ters can	be assigned values using assignment  operators	inside	arith-
       metic  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
	      details.
	      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
	      option, 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
	      replaced 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
	      escape codes) by prefixing your prompt with a non-printing char-
	      acter (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
	      exceeded,	the shell exits.

       TMPDIR The directory shell temporary files are  created	in.   If  this
	      parameter	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
       occurring  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
       unchanged).  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
	      instead  of  the	end  of	the list.  Also, a !  appearing	at the
	      start of the list	has special meaning (see below), so to	repre-
	      sent itself 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
	      except `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
	      noclobber	 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
	      instead 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
	      descriptor, 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
       appear 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
       numeric	arguments  to the test command,	and as the value of an assign-
       ment 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
		     operator, 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
       using  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
       between 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
       inside  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
       attribute  of  functions	 is  currently not used.  In the original Korn
       shell, exported functions are visible to	shell scripts  that  are  exe-
       cuted.

       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
       desirable).

       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
	      descriptions  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
       using the PATH parameter.  The checks are  made	in  the	 above	order.
       Special	built-in  commands differ from other commands in that the PATH
       parameter 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
       parameter  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
	      options 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
	      attribute	(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
	      below 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
	      description.

       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
	      directory	$HOME is used.	If dir	is  -,	the  previous  working
	      directory	is used	(see OLDPWD parameter).	 If -L option (logical
	      path) is used or if the physical option (see set command	below)
	      isn't set, references to .. in dir are relative to the path used
	      get to the directory.  If	-P option (physical path) is  used  or
	      if  the physical option is set, .. is relative to	the filesystem
	      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
	      exactly  as  if  the  command  had  not been specified, with two
	      exceptions: first, cmd cannot be a shell function,  and  second,
	      special  built-in	 commands  lose	their specialness (i.e., redi-
	      rection 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 ?
	      parameter.

       export [-p] [parameter[=value]] ...
	      Sets the export attribute	of  the	 named	parameters.   Exported
	      parameters  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
	      option is	used, in  which	 case  export  commands	 defining  all
	      exported 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
	      default) 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
	      introduced 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
	      argument)	 argument  that	 does not start	with a -, or when a --
	      argument is encountered.

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

	      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
	      option  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
	      description 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
	      expression,  the	exit  status is	greater	than 1.	 Since expres-
	      sions 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
	      (inclusive of any	separating  spaces).   If  no  parameters  are
	      specified,  the REPLY parameter is used.	If the input line ends
	      in a backslash and the -r	option was not used, the backslash and
	      newline  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
	      appended	to  it,	 in  which case	the string is used as a	prompt
	      (printed to standard error before	any  input  is	read)  if  the
	      input 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
	      attribute.  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
	      options, set the positional parameters, or set an	array  parame-
	      ter.   Options can be changed using the +-o option syntax, where
	      option is	the long name of an option, or using the +-letter syn-
	      tax,  where  letter  is the option's single letter name (not all
	      options have a single letter name).  The following  table	 lists
	      both  option letters (if they exist) and long names along	with a
	      description 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
						occurs	 or  a	command	 fails
						(i.e., exits with  a  non-zero
						status).   This	does not apply
						to commands whose exit	status
						is   explicitly	 tested	 by  a
						shell construct	 such  as  if,
						until,	while, && or ||	state-
						ments.
	       -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
						description   of   what	  this
						means.
	       -s	  stdin			If  used  when	the  shell  is
						invoked,  commands  are	  read
						from   standard	  input.   Set
						automatically 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
						being 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
						default.   Note	 that  setting
						this option  does  not	effect
						the  current  value of the PWD
						parameter; 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
				    potential  for  problems  if
				    str	turns out to be	an oper-
				    ator (e.g.,	-r) - it is gen-
				    erally 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
				    device.
	       -p file		    file is a named pipe.
	       -u file		    file's  mode  has setuid bit
				    set.
	       -g file		    file's mode	has  setgid  bit
				    set.
	       -k file		    file's  mode  has sticky bit
				    set.
	       -s file		    file is not	empty.
	       -O file		    file's owner is the	 shell's
				    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
				    exist (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
				    device.  If	the posix option
				    (set  -o  posix,  see  POSIX
				    Mode above)	is not	set,  fd
				    may	 be  left  out,	in which
				    case it is	taken  to  be  1
				    (the  behaviour  differs due
				    to the special  POSIX  rules
				    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,
	      indicating  the signals are to be	ignored, a minus (-), indicat-
	      ing that the default action is to	be taken for the signals  (see
	      signal(2	or  3)),  or  a	string containing shell	commands to be
	      evaluated	and executed at	the first opportunity (i.e., when  the
	      current  command	completes,  or	before	printing  the next PS1
	      prompt) after receipt of one of the signals.  Signal is the name
	      of  a  signal  (e.g.,  PIPE or ALRM) or the number of the	signal
	      (see kill	-l command above).  There  are	two  special  signals:
	      EXIT  (also  known  as  0),  which is executed when the shell is
	      about to exit, and ERR which is executed after an	 error	occurs
	      (an error	is something that would	cause the shell	to exit	if the
	      -e or errexit option were	set -- see set command	above).	  EXIT
	      handlers	are  executed  in the environment of the last executed
	      command.	Note that for non-interactive shells, the trap handler
	      cannot  be  changed for signals that were	ignored	when the shell
	      started.

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

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

       true   A	command	that exits with	a zero value.

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

	      If name arguments	are given, the attributes of the named parame-
	      ters  are	 set  (-)  or  cleared (+).  Values for	parameters may
	      optionally 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
	      reported.

	       -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
				 expressions.
	       -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
	      directory	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
	      already 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
	      below 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
				 error 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
       enabled.	 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
       control	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
	      although	only  two  prefix  characters (usually ESC and ^X) are
	      supported, 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
	      sequences	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
	      replaced by the given substitute string, which may contain edit-
	      ing 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
       default 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
	      appended.	 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
	      indicators 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
	      exchanges	 the  two previous characters; otherwise, it exchanges
	      the previous and current characters and  moves  the  cursor  one
	      character	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
		     inserted.

	      #	     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
		     expansion 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
		     directory.	  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
		     another 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
		     position.

       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
       include 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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