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KSH(1)			  BSD General Commands Manual			KSH(1)

NAME
     ksh, rksh -- public domain	Korn shell

SYNOPSIS
     ksh [-+abCefhiklmnpruvXx] [-+o option]
	 [-c string | -s | file	[argument ...]]

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

     The options are as	follows:

     -c	string
	     ksh will execute the command(s) contained in string.

     -i	     Interactive shell.	 A shell is "interactive" if this option is
	     used or if	both standard input and	standard error are attached to
	     a tty(4).	An interactive shell has job control enabled, ignores
	     the SIGINT, SIGQUIT, and SIGTERM signals, and prints prompts be-
	     fore reading input	(see the PS1 and PS2 parameters).  For non-in-
	     teractive shells, the trackall option is on by default (see the
	     set command below).

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

     -p	     Privileged	shell.	A shell	is "privileged"	if this	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)	and getgid(2)).	 A privileged
	     shell does	not process $HOME/.profile nor the ENV parameter (see
	     below).  Instead, the file	/etc/suid_profile is processed.
	     Clearing the privileged option causes the shell to	set its	effec-
	     tive user ID (group ID) to	its real user ID (group	ID).

     -r	     Restricted	shell.	A shell	is "restricted"	if this	option is
	     used; if the basename the shell was invoked with was "rksh"; or
	     if	the SHELL parameter is set to "rksh".  The following restric-
	     tions 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 cannot be changed.
	     +o	 Command names can't be	specified with absolute	or relative
		 paths.
	     +o	 The -p	option of the built-in command command can't be	used.
	     +o	 Redirections that create files	can't be used (i.e. `>', `>|',
		 `>>', `<>').

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

     In	addition to the	above, the options described in	the set	built-in com-
     mand can also be used on the command line:	both [-+abCefhkmnuvXx] and
     [-+o option] can be used for single letter	or long	options, respectively.

     If	neither	the -c nor the -s option is 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 the
     standard input.  The name of the shell (i.e. the contents of $0) is de-
     termined 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 basename the shell was
     called with (i.e. argv[0])	is used.

     If	the ENV	parameter is set when an interactive 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.  In order to	have
     an	interactive (as	opposed	to login) shell	process	a startup file,	ENV
     may be set	and exported (see below) in $HOME/.profile - future interac-
     tive shell	invocations will process any file pointed to by	$ENV:

	   export ENV=$HOME/.kshrc

     $HOME/.kshrc is then free to specify instructions for interactive shells.
     For example, the global configuration file	may be sourced:

	   . /etc/ksh.kshrc

     The above strategy	may be employed	to keep	setup procedures for login
     shells in $HOME/.profile and setup	procedures for interactive shells in
     $HOME/.kshrc.  Of course, since login shells are also interactive,	any
     commands placed in	$HOME/.kshrc will be executed by login shells too.

     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 oc-
     curred 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 com-
     mand 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 whitespace
     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-charac-
     ters 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 cre-
     ate co-processes (see Co-processes	below);	`;' is used to separate	com-
     mands; `&'	is used	to create asynchronous pipelines; `&&' and `||'	are
     used to specify conditional execution; `;;' is used in case statements;
     `(( .. ))'	is used	in arithmetic expressions; and lastly, `( .. )'	is
     used to create subshells.

     Whitespace	and meta-characters can	be quoted individually using a back-
     slash (`\'), or in	groups using double (`"') or single (`'') quotes.  The
     following characters are also treated specially by	the shell and must be
     quoted if they are	to represent themselves: `\', `"', `'',	`#', `$', ``',
     `~', `{', `}', `*', `?', and `['.	The first three	of these are the above
     mentioned quoting characters (see Quoting below); `#', if used at the be-
     ginning of	a word,	introduces a comment --	everything after the `#' up to
     the nearest newline is ignored; `$' is used to introduce parameter, com-
     mand, and arithmetic substitutions	(see Substitution below); ``' intro-
     duces an old-style	command	substitution (see Substitution below); `~' be-
     gins a directory expansion	(see Tilde expansion below); `{' and `}' de-
     limit 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 exe-
     cuted, and	compound-commands, such	as for and if statements, grouping
     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 pa-
     rameter assignments come before any command words.	 The command words, if
     any, define the command that is to	be executed and	its arguments.	The
     command may be a shell built-in command, a	function, or an	external com-
     mand (i.e.	a separate executable file that	is located using the PATH pa-
     rameter; see Command execution below).

     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 sta-
     tus is 126).  The exit status of other command constructs (built-in com-
     mands, 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 assign-
     ment or 0 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	status
     of	a pipeline is that of its last command.	 A pipeline may	be prefixed by
     the `!' reserved word, which causes the exit status of the	pipeline to be
     logically complemented: if	the original status was	0, the complemented
     status will be 1; if the original status was not 0, the complemented sta-
     tus will be 0.

     Lists of commands can be created by separating pipelines by any of	the
     following tokens: `&&', `||', `&',	`|&', and `;'.	The first two are for
     conditional execution: "cmd1 && cmd2" executes cmd2 only if the exit sta-
     tus 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 `&&' and `||' operators are "left-associative".  For ex-
     ample, both of these commands will	print only "bar":

	   $ false && echo foo || echo bar
	   $ true || echo foo && echo bar

     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 SIGINT and	SIGQUIT	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 a spe-
     cial kind of asynchronous process (see Co-processes below).  A command
     must follow the `&&' and `||' operators, while it need not	follow `&',
     `|&', or `;'.  The	exit status of a list is that of the last command exe-
     cuted, with the exception of asynchronous lists, for which	the exit sta-
     tus 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 as-
     signments or redirections):

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

     Note: Some	shells (but not	this one) execute control structure commands
     in	a subshell when	one or more of their file descriptors are redirected,
     so	any environment	changes	inside them may	fail.  To be portable, 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 semicolon, a
     newline, or a (syntactically correct) reserved word.  For example,	the
     following are all valid:

	   $ { echo foo; echo bar; }
	   $ { echo foo; echo bar<newline> }
	   $ { { echo foo; echo	bar; } }

     This is not valid:

	   $ { echo foo; echo bar }

     (list)  Execute list in a subshell.  There	is no implicit way to pass en-
	     vironment 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 a specified
	     pattern; 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 re-
	     strictions	regarding `.' and `/' are dropped.  Note that any un-
	     quoted space before and after a pattern is	stripped; any space
	     within 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	...]]; do list;	done
	     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 spec-
	     ify 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	there are no items, list is not	executed and 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 fol-
	     lowing the	else is	executed.  The exit status of an if statement
	     is	that of	non-conditional	list that is executed; if no non-con-
	     ditional list is executed,	the exit status	is zero.

     select name [in word ...];	do list; done
	     The select	statement provides an automatic	method of presenting
	     the user with a menu and selecting	from it.  An enumerated	list
	     of	the specified word(s) is printed on standard error, followed
	     by	a prompt (PS3: normally	`#? ').	 A number corresponding	to one
	     of	the enumerated words is	then read from standard	input, name is
	     set to the	selected word (or 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 reprinted without
	     executing list.

	     When list completes, the enumerated list is printed if REPLY is
	     NULL, the prompt is printed, and so on.  This process 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 statement 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 pre-checked 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 redi-
	     rections 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 sec-
	     tion.

     ((	expression ))
	     The arithmetic expression expression is evaluated;	equivalent to
	     let expression (see Arithmetic expressions	and the	let command,
	     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', `=', `!') must be unquoted.

		   +o   The second operand of the `!=' and `=' expressions are
		       patterns	(e.g. the comparison [[	foobar = f*r ]]	suc-
		       ceeds).

		   +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, re-
		       spectively.

		   +o   The single argument form	of test, which tests if	the
		       argument	has a non-zero length, is not valid; explicit
		       operators must always be	used e.g. instead of [ str ]
		       use [[ -n str ]].

		   +o   Parameter, command, and arithmetic substitutions	are
		       performed as expressions	are evaluated and lazy expres-
		       sion evaluation is used for the `&&' and	`||' opera-
		       tors.  This means that in the following statement, $(<
		       foo) is evaluated if and	only if	the file foo exists
		       and is readable:

			     $ [[ -r foo && $(<	foo) = b*r ]]

   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
     substitution) except no field splitting is	carried	out on the results of
     double-quoted substitutions.  If a	`\' inside a double-quoted string is
     followed by `\', `$', ``',	or `"',	it is replaced by the second charac-
     ter; if it	is followed by a newline, both the `\' and the newline are
     stripped; otherwise, both the `\' and the character following are un-
     changed.

   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. substitutes
     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	com-
     mand 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'
	   nohup='nohup	'
	   r='fc -s'
	   stop='kill -STOP'

     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 command.  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(1),	cc(1), chmod(1), cp(1),	date(1),
     ed(1), emacs, grep(1), ls(1), mail(1), make(1), mv(1), pr(1), rm(1),
     sed(1), sh(1), vi(1), and who(1).

   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 substitu-
     tions, 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	whitespace".  Sequences	of one or more
     IFS whitespace characters,	in combination with zero or one	non-IFS	white-
     space characters, delimit a field.	 As a special case, leading and	trail-
     ing IFS whitespace	is stripped (i.e. no leading or	trailing empty field
     is	created	by it);	leading	non-IFS	whitespace does	create an empty	field.

     Example: If IFS is	set to "<space>:", and VAR is set to
     "<space>A<space>:<space><space>B::D", the substitution for	$VAR results
     in	four fields: `A', `B', `' (an empty field), 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.

     Also, note	that the field splitting applies only to the immediate result
     of	the substitution.  Using the previous example, the substitution	for
     $VAR:E results in the fields: `A',	`B', `', and `D:E', not	`A', `B', `',
     `D', and `E'.  This behavior is POSIX compliant, but incompatible with
     some other	shell implementations which do field splitting on the word
     which contained the substitution or use IFS as a general whitespace de-
     limiter.

     The results of substitution are, unless otherwise specified, also subject
     to	brace expansion	and file name expansion	(see the relevant sections be-
     low).

     A command substitution is replaced	by the output generated	by the speci-
     fied command, which is run	in a subshell.	For $(command) substitutions,
     normal quoting rules are used when	command	is parsed; however, for	the
     `command` form, a `\' followed by any of `$', ``',	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.  Note that $(< foo) has the same effect
     as	$(cat foo), but	it is carried out more efficiently because no process
     is	started.

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

   Parameters
     Parameters	are shell variables; they can be assigned values and their
     values can	be accessed using a parameter substitution.  A parameter name
     is	either one of the special single punctuation or	digit character	param-
     eters described below, or a letter	followed by zero or more letters or
     digits (`_' counts	as a letter).  The latter form can be treated as ar-
     rays by appending an array	index of the form [expr] where expr is an
     arithmetic	expression.  Parameter substitutions take the form $name,
     ${name}, or ${name[expr]} where name is a parameter name.	If expr	is a
     literal `@' then the named	array is expanded using	the same quoting rules
     as	`$@', while if expr is a literal `*' then the named array is expanded
     using the same quoting rules as `$*'.  If substitution is performed on a
     parameter (or an array parameter element) 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', and `$'; this is the
     only way the special single character parameters are set.	Second,	param-
     eters are imported	from the shell's environment at	startup.  Third, pa-
     rameters can be assigned values on	the command line: for example, FOO=bar
     sets the parameter	"FOO" to "bar";	multiple parameter assignments can be
     given on a	single command line and	they can be followed by	a simple-com-
     mand, in which case the assignments are in	effect only for	the duration
     of	the command (such assignments are also exported; see below for the im-
     plications	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 sec-
     tion.  Fifth, for and select loops	set parameters as well as the getopts,
     read, and set -A commands.	 Lastly, parameters can	be assigned values us-
     ing assignment operators inside arithmetic	expressions (see Arithmetic
     expressions below)	or using the ${name=value} form	of the parameter sub-
     stitution (see below).

     Parameters	with the export	attribute (set using the export	or typeset -x
     commands, or by parameter assignments followed by simple commands)	are
     put in the	environment (see environ(7)) of	commands run by	the shell as
     name=value	pairs.	The order in which parameters appear in	the environ-
     ment of a command is unspecified.	When the shell starts up, it extracts
     parameters	and their values from its environment and automatically	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 oc-
	     curs (normally causing termination	of a shell script, function,
	     or	script sourced using the `.' built-in).	 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 substitution
     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 not
	     specified;	otherwise 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, and two of them result
	     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 can-
     not 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 ($1, $2, etc.).

     $	      The PID of the shell, or the PID of the original shell if	it is
	      a	subshell.  Do NOT use this mechanism for generating temporary
	      file names; see mktemp(1)	instead.

     -	      The concatenation	of the current single letter options (see the
	      set command below	for a 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 of the shell, determined	as follows: the	first argument
	      to ksh if	it was invoked with the	-c option and arguments	were
	      given; otherwise the file	argument, if it	was supplied; or else
	      the basename the shell was invoked with (i.e. argv[0]).  $0 is
	      also set to the name of the current script or the	name of	the
	      current function,	if it was defined with the function keyword
	      (i.e. a Korn shell style function).

     1 ... 9  The first	nine positional	parameters that	were supplied to the
	      shell, function, or script sourced using the `.' built-in.  Fur-
	      ther 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 separate
	      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 losing	NULL
	      arguments	or splitting arguments with spaces.

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

     _ (underscore)
		When an	external command is executed by	the shell, this	param-
		eter 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	previ-
		ous command.  When MAILPATH messages are evaluated, this pa-
		rameter	contains the name of the file that changed (see	the
		MAILPATH parameter, below).

     CDPATH	Search path for	the cd built-in	command.  It works the same
		way as PATH for	those directories not beginning	with `/' or
		`.' in cd commands.  Note that if CDPATH is set	and does not
		contain	`.' or contains	an empty path, the current directory
		is not searched.  Also,	the cd built-in	command	will display
		the resulting directory	when a match is	found in any search
		path other than	the empty path.

     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 the select, set -o, and kill	-l
		commands to format information columns.

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

		Note: traditionally, EDITOR was	used to	specify	the name of an
		(old-style) line editor, such as ed(1),	and VISUAL was used to
		specify	a (new-style) screen editor, such as vi(1).  Hence if
		VISUAL is set, it overrides EDITOR.

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

     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.

     HISTCONTROL
		A colon	separated list of history settings.  If	ignoredups is
		present, lines identical to the	previous history line will not
		be saved.  If ignorespace is present, lines starting with a
		space will not be saved.  Unknown settings are ignored.

     HISTFILE	The name of the	file used to store command history.  When as-
		signed to, history is loaded from the specified	file.  Also,
		several	invocations of the shell running on the	same machine
		will share history if their HISTFILE parameters	all point to
		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.

     HISTSIZE	The number of commands normally	stored for history.  The de-
		fault is 500.

     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; nor-
		mally 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 the shell and the date the version was created
		(read-only).

     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.

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

     MAILCHECK	How often, in seconds, the shell will check for	mail in	the
		file(s)	specified by MAIL or MAILPATH.	If set to 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
		separated, and each file may be	followed by a `?' and a	mes-
		sage to	be printed if new mail has arrived.  Command, parame-
		ter, and arithmetic substitution is performed on the message
		and, during substitution, the parameter	$_ contains the	name
		of the file.  The default message is "you have mail in $_".

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

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

     OPTIND	The index of the next argument to be processed when using
		getopts.  Assigning 1 to this parameter	causes getopts to
		process	arguments from the beginning the next time it is in-
		voked.

     PATH	A colon	separated list of directories that are searched	when
		looking	for commands and files sourced using the `.' command
		(see below).  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 (read-only).

     PS1	The primary prompt for interactive shells.  Parameter, com-
		mand, and arithmetic substitutions are performed, and the
		prompt string can be customised	using backslash-escaped	spe-
		cial characters.

		Note that since	the command-line editors try to	figure out how
		long the prompt	is (so they know how far it is to the 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 using	the \[...\] substitution (see
		below) or by prefixing your prompt with	a non-printing charac-
		ter (such as control-A)	followed by a carriage return and then
		delimiting the escape codes with this non-printing character.
		By the way, don't blame	me for this hack; it's in the original
		ksh.

		The default prompt is the first	part of	the hostname, followed
		by `$ '	for non-root users, `# ' for root.

		The following backslash-escaped	special	characters can be used
		to customise the prompt:

		\a	      Insert an	ASCII bell character.
		\d	      The current date,	in the format "Day Month Date"
			      for example "Wed Nov 03".
		\D{format}    The current date,	with format converted by
			      strftime(3).  The	braces must be specified.
		\e	      Insert an	ASCII escape character.
		\h	      The hostname, minus domain name.
		\H	      The full hostname, including domain name.
		\j	      Current number of	jobs running (see Job control
			      below).
		\l	      The controlling terminal.
		\n	      Insert a newline character.
		\r	      Insert a carriage	return character.
		\s	      The name of the shell.
		\t	      The current time,	in 24-hour HH:MM:SS format.
		\T	      The current time,	in 12-hour HH:MM:SS format.
		\@	      The current time,	in 12-hour HH:MM:SS AM/PM for-
			      mat.
		\A	      The current time,	in 24-hour HH:MM format.
		\u	      The current user's username.
		\v	      The current version of ksh.
		\V	      Like `\v', but more verbose.
		\w	      The current working directory.  $HOME is abbre-
			      viated as	`~'.
		\W	      The basename of the current working directory.
			      $HOME is abbreviated as `~'.
		\!	      The current history number.  An unescaped	`!'
			      will produce the current history number too, as
			      per the POSIX specification.  A literal `!' can
			      be put in	the prompt by placing `!!' in PS1.
		\#	      The current command number.  This	could be dif-
			      ferent to	the current history number, if
			      HISTFILE contains	a history list from a previous
			      session.
		\$	      The default prompt character i.e.	`#' if the ef-
			      fective UID is 0,	otherwise `$'.	Since the
			      shell interprets `$' as a	special	character
			      within double quotes, it is safer	in this	case
			      to escape	the backslash than to try quoting it.
		\nnn	      The octal	character nnn.
		\\	      Insert a single backslash	character.
		\[	      Normally the shell keeps track of	the number of
			      characters in the	prompt.	 Use of	this sequence
			      turns off	that count.
		\]	      Use of this sequence turns the count back	on.

		Note that the backslash	itself may be interpreted by the
		shell.	Hence, to set PS1 either escape	the backslash itself,
		or use double quotes.  The latter is more practical:

		      PS1="\u "

		This is	a more complex example,	which does not rely on the
		above backslash-escaped	sequences.  It embeds the current
		working	directory, in reverse video, in	the prompt string:

		      x=$(print	\\001)
		      PS1="$x$(print \\r)$x$(tput so)$x\$PWD$x$(tput se)$x> "

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

     PS3	Prompt used by the select statement when reading a menu	selec-
		tion.  The default is `#? '.

     PS4	Used to	prefix commands	that are printed during	execution
		tracing	(see the set -x	command	below).	 Parameter, command,
		and arithmetic substitutions are performed before it is
		printed.  The default is `+ '.

     PWD	The current working directory.	May be unset or	NULL if	the
		shell doesn't know where it is.

     RANDOM	A random number	generator.  Every time RANDOM is referenced,
		it is assigned the next	random number in the range 0-32767.
		By default, arc4random(3) is used to produce values.  If the
		variable RANDOM	is assigned a value, the value is used as the
		seed to	srand_deterministic(3) and subsequent references of
		RANDOM produce a predictable sequence.

     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 pa-
		rameter	has been assigned an integer value, the	number of sec-
		onds since the assignment plus the value that was assigned.

     TERM	The user's terminal type.  If set, it will be used to deter-
		mine the escape	sequence used to clear the screen.

     TMOUT	If set to a positive integer in	an interactive shell, it spec-
		ifies 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 temporary	shell 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
		specified in this parameter contains the string	"vi", "emacs",
		or "gmacs", the	vi(1), emacs, or gmacs (Gosling	emacs) editing
		mode is	enabled, respectively.	See also the EDITOR parameter,
		above.

   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
     OLDPWD parameter is substituted, respectively.  Otherwise,	the password
     file is searched for the login name, and the tilde	expression is substi-
     tuted 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 (such as those preceding a simple-command	or
     those occurring in	the arguments of alias,	export,	readonly, and
     typeset), tilde expansion is done after any assignment (i.e. after	the
     equals sign) or after an unquoted colon (`:'); login names	are also de-
     limited 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 take the	following form:

	   prefix{str1,...,strN}suffix

     The expressions are expanded to N words, each of which is the concatena-
     tion of prefix, stri, and suffix (e.g. "a{c,b{X,Y},d}e" expands to	four
     words: "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
     (e.g. {} and {foo}	are not	expanded).  Brace expansion is carried out af-
     ter parameter 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 mean-
     ing:

     ?	     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	to 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 rep-
	     resent itself it must be quoted or	appear later in	the list.

	     Within a bracket expression, the name of a	character class	en-
	     closed in `[:' and	`:]' stands for	the list of all	characters be-
	     longing to	that class.  Supported character classes:

		   alnum   cntrl   lower   space
		   alpha   digit   print   upper
		   blank   graph   punct   xdigit

	     These match characters using the macros specified in isalnum(3),
	     isalpha(3), and so	on.  A character class may not be used as an
	     endpoint of a range.

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

     *(pattern|...|pattern)
	     Matches any string	of characters that matches zero	or more	occur-
	     rences 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 occur-
	     rences of the specified patterns.	Example: The pattern
	     +(foo|bar)	matches	the strings "foo", "bar", "foobar", 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.  Ex-
	     ample: The	pattern	@(foo|bar) only	matches	the strings "foo" and
	     "bar".

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

     Unlike most shells, ksh never matches `.' and `..'.

     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 `/'.

   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 pipe-
     lines, for	which standard input and/or standard output are	those set up
     by	the pipeline, asynchronous commands created when job control is	dis-
     abled, for	which standard input is	initially set to be from /dev/null,
     and commands for which any	of the following redirections have been	speci-
     fied:

     > 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 if file exists it is appended to	instead	of be-
	     ing 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 read-
	     ing.

     <>	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 redi-
	     rected from the temporary file.  If marker	contains no quoted
	     characters, the contents of the temporary file are	processed as
	     if	enclosed in double quotes each time the	command	is executed,
	     so	parameter, command, and	arithmetic substitutions are per-
	     formed, along with	backslash (`\')	escapes	for `$', ``', `\', and
	     `\newline'.  If multiple here documents are used on the same com-
	     mand line,	they are saved in order.

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

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

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

     In	any of the above redirections, the file	descriptor that	is redirected
     (i.e. standard input or standard output) can be explicitly	given by pre-
     ceding the	redirection with a single digit.  Parameter, command, and
     arithmetic	substitutions, tilde substitutions, and	(if the	shell is in-
     teractive)	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	multi-
     ple files match, the word with the	expanded file name generation charac-
     ters 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 created and in
     the order they are	given, so the following	will print an error with a
     line number prepended to it:

	   $ cat /foo/bar 2>&1 > /dev/null | cat -n

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

     Expressions may contain alpha-numeric parameter identifiers, array	refer-
     ences, and	integer	constants and may be combined with the following C op-
     erators (listed and grouped in increasing order of	precedence):

     Unary operators:

	   + - ! ~ ++ --

     Binary operators:

	   ,
	   = *=	/= %= += -= <<=	>>= &= ^= |=
	   ||
	   &&
	   |
	   ^
	   &
	   == !=
	   < <=	>= >
	   << >>
	   + -
	   * / %

     Ternary operators:

	   ?: (precedence is immediately higher	than assignment)

     Grouping operators:

	   ( )

     A parameter that is NULL or unset evaluates to 0.	Integer	constants may
     be	specified with arbitrary bases using the notation base#number, where
     base is a decimal integer specifying the base, and	number is a number in
     the specified base.  Additionally,	integers may be	prefixed with `0X' or
     `0x' (specifying base 16) or `0' (base 8) in all forms of arithmetic ex-
     pressions,	except as numeric arguments to the test	command.

     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 oper-
		   ator, the result is the original value of the parameter.

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

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

	   =	   Assignment; the 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>, with any operator precedence in
		   <expr> preserved.  For example, "var1 *= 5 +	3" is the same
		   as specifying "var1 = var1 *	(5 + 3)".

	   ||	   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) XOR (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 the
		   result is <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's input has been	redirected us-
     ing an exec n>&p redirection.  If a co-process's input is redirected in
     this way, the next	co-process to be started will share the	output with
     the first co-process, unless the output of	the initial co-process has
     been redirected using an exec n<&p	redirection.

     Some notes	concerning co-processes:

     +o	 The only way to close the co-process's	input (so the co-process reads
	 an end-of-file) is to redirect	the input to a numbered	file descrip-
	 tor 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's 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 behaviour is slightly different from the
	 original Korn shell which closes its copy of the write	portion	of the
	 co-process 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 true	if the co-process in-
	 put has been duplicated to another file descriptor and	print -un is
	 used.

   Functions
     Functions are defined using either	Korn shell function function-name syn-
     tax or the	Bourne/POSIX shell function-name() syntax (see below for the
     difference	between	the two	forms).	 Functions are like .-scripts (i.e.
     scripts sourced using the `.' built-in) in	that they are executed in the
     current environment.  However, unlike .-scripts, shell arguments (i.e.
     positional	parameters $1, $2, etc.) are never visible inside them.	 When
     the shell is determining the location of a	command, functions are
     searched after special built-in commands, before regular 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 defini-
     tions can be listed using typeset -f.  The	autoload command (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 specified in
     the FPATH parameter for a file with the same name as the function,	which,
     if	found, is read and executed.  If after executing the file the named
     function is found to be defined, the function is executed;	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 function's
     duration; otherwise, the xtrace option is turned off.  The	"export" at-
     tribute of	functions is currently not used.  In the original Korn shell,
     exported functions	are visible to shell scripts that are executed.

     Since functions are executed in the current shell environment, parameter
     assignments made inside functions are visible after the function com-
     pletes.  If this is not the desired effect, the typeset command can be
     used inside a function to create a	local parameter.  Note that special
     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 differently
     in	the following ways from	functions defined with the () notation:

     +o	 The $0	parameter is set to the	name of	the function (Bourne-style
	 functions leave $0 untouched).

     +o	 Parameter assignments preceding function calls	are not	kept in	the
	 shell environment (executing Bourne-style functions will keep assign-
	 ments).

     +o	 OPTIND	is saved/reset and restored on entry and exit from the func-
	 tion 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).

   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 contains
     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	 kill -l output.  In POSIX mode, only signal names are listed (in a
	 single	line); in non-POSIX mode, signal numbers, names, and descrip-
	 tions are printed (in columns).

     +o	 echo options.	In POSIX mode, -e and -E are not treated as options,
	 but printed like other	arguments; in non-POSIX	mode, these options
	 control the interpretation of backslash sequences.

     +o	 fg exit status.  In POSIX mode, the exit status is 0 if no errors oc-
	 cur; in non-POSIX mode, the exit status is that of the	last fore-
	 grounded job.

     +o	 eval exit status.  If eval gets to see	an empty command (i.e. 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 is enabled.
	 Note that set -o posix	(or setting the	POSIXLY_CORRECT	parameter) au-
	 tomatically turns the braceexpand option off; however,	it can be ex-
	 plicitly turned on later.

     +o	 set -.	 In POSIX mode,	this does not clear the	verbose	or xtrace op-
	 tions;	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 com-
	 mand substitutions performed in generating the	set command.  For ex-
	 ample,	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 the alias, export, readonly, and	typeset	com-
	 mands.	 In POSIX mode,	normal argument	expansion is done; in non-
	 POSIX mode, field splitting, file globbing, brace expansion, and
	 (normal) tilde	expansion are turned off, while	assignment tilde ex-
	 pansion 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 always be digits.

     +o	 Alias expansion.  In POSIX mode, alias	expansion is only carried out
	 when reading command words; in	non-POSIX mode,	alias expansion	is
	 carried out on	any word following an alias that ended in a space.
	 For example, the following for	loop uses parameter `i'	in POSIX mode
	 and `j' in non-POSIX mode:

	       alias a='for ' i='j'
	       a i in 1	2; do echo i=$i	j=$j; done

     +o	 test.	In POSIX mode, the expression `-t' (preceded by	some number 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(4) (i.e. the
	 fd argument to	the -t test may	be left	out and	defaults to 1).

   Strict Bourne shell mode
     When the sh option	is enabled (see	the set	command), ksh will behave like
     sh(1) in the following ways:

     +o	 The parameter $_ is not set to:

	 -   the expanded alias' full program path after entering commands
	     that are tracked aliases
	 -   the last argument on the command line after entering external
	     commands
	 -   the file that changed when	MAILPATH is set	to monitor a mailbox

     +o	 File descriptors are left untouched when executing exec with no argu-
	 ments.

     +o	 Backslash-escaped special characters are not substituted in PS1.

     +o	 Sequences of `((...))'	are not	interpreted as arithmetic expressions.

   Command execution
     After evaluation of command-line arguments, redirections, and parameter
     assignments, the type of command is determined: a special built-in, a
     function, a regular built-in, or the name of a file to execute found us-
     ing the PATH parameter.  The checks are made in the above order.  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 speci-
     fied before the command are kept after the	command	completes.  Just to
     confuse things, if	the posix option is turned off (see the	set command
     below), some special commands are very special in that no field split-
     ting, file	globbing, brace	expansion, nor tilde expansion is performed on
     arguments that look like assignments.  Regular built-in commands are dif-
     ferent only in that the PATH parameter is not used	to find	them.

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

     POSIX special commands

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

     Additional	ksh special commands

     builtin, typeset

     Very special commands (when POSIX mode is off)

     alias, readonly, set, typeset

     POSIX regular commands

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

     Additional	ksh regular commands

     [,	echo, let, print, suspend, test, ulimit, whence

     Once the type of 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 [arg ...]
	     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 po-
	     sitional parameters are those of the environment the command is
	     used in.

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

     alias [-d | -t [-r] | +-x]	[-p] [+] [name [=value]	...]
	     Without arguments,	alias lists all	aliases.  For any name without
	     a value, the existing alias is listed.  Any name with a value de-
	     fines an alias (see Aliases above).

	     When listing aliases, one of two formats is used.	Normally,
	     aliases are listed	as name=value, where value is quoted.  If op-
	     tions were	preceded with `+', or a	lone `+' is given on the com-
	     mand line,	only name is printed.

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

	     If	the -p option is used, each alias is prefixed with the string
	     "alias ".

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

     bg	[job ...]
	     Resume the	specified stopped job(s) in the	background.  If	no
	     jobs are specified, %+ is assumed.	 See Job control below for
	     more information.

     bind [-l]
	     The current bindings are listed.  If the -l flag is given,	bind
	     instead lists the names of	the functions to which keys may	be
	     bound.  See Emacs editing mode for	more information.

     bind [-m] string=[substitute] ...
     bind string=[editing-command] ...
	     In	Emacs editing mode, the	specified editing command is bound to
	     the given string.	Future input of	the string will	cause the
	     editing command to	be immediately invoked.	 Bindings have no ef-
	     fect in Vi	editing	mode.

	     If	the -m flag is given, the specified input string will after-
	     wards be immediately replaced by the given	substitute string,
	     which may contain editing commands.  Control characters may be
	     written using caret notation.  For	example, ^X represents Con-
	     trol-X.

	     If	a certain character occurs as the first	character of any bound
	     multi-character string sequence, that character becomes a command
	     prefix character.	Any character sequence that starts with	a com-
	     mand prefix character but that is not bound to a command or sub-
	     stitute is	implicitly considered as bound to the `error' command.
	     By	default, two command prefix characters exist: Escape (^[) and
	     Control-X (^X).

	     The following default bindings show how the arrow keys on an ANSI
	     terminal or xterm are bound (of course some escape	sequences
	     won't work	out quite this nicely):

		   bind	'^[[A'=up-history
		   bind	'^[[B'=down-history
		   bind	'^[[C'=forward-char
		   bind	'^[[D'=backward-char

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

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

     cd	[-LP] [dir]
	     Set the working directory to dir.	If the parameter CDPATH	is
	     set, it lists the search path for the directory containing	dir.
	     A NULL path means the current directory.  If dir is found in any
	     component of the CDPATH search path other than the	NULL path, the
	     name of the new working directory will be written to standard
	     output.  If dir is	missing, the home directory HOME is used.  If
	     dir is `-', the previous working directory	is used	(see the
	     OLDPWD parameter).

	     If	the -L option (logical path) is	used or	if the physical	option
	     isn't set (see the	set command below), references to `..' in dir
	     are relative to the path used to get to the directory.  If	the -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
	     working 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	[arg ...]
	     If	neither	the -v nor -V option is	given, cmd is executed exactly
	     as	if command had not been	specified, with	two exceptions:
	     firstly, cmd cannot be an alias or	a shell	function; and sec-
	     ondly, special built-in commands lose their specialness (i.e. re-
	     direction 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 POSIX-ish systems, it	is the value
	     returned by getconf PATH).	 Nevertheless, reserved	words,
	     aliases, shell functions, and builtin commands are	still found
	     before external commands.

	     If	the -v option is given,	instead	of executing cmd, information
	     about what	would be executed is given (and	the same is done for
	     arg ...).	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 searching
	     the PATH parameter, the full path of the command is printed.  If
	     no	command	is found (i.e. the path	search fails), nothing is
	     printed and command exits with a non-zero status.	The -V option
	     is	like the -v option, except it is more verbose.

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

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

	     The options are provided for compatibility	with BSD shell
	     scripts.  The -n option suppresses	the trailing newline, -e en-
	     ables backslash interpretation (a no-op, since this is normally
	     done), and	-E suppresses backslash	interpretation.	 If the	posix
	     option is set, only the first argument is treated as an option,
	     and only if it is exactly "-n".

     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 command is given except for I/O redirection,	the I/O	redi-
	     rection is	permanent and the shell	is not replaced.  Any file de-
	     scriptors greater than 2 which are	opened or dup(2)'d 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 $? parame-
	     ter.

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

	     If	no parameters are specified, the names of all parameters with
	     the export	attribute are printed one per line, unless the -p op-
	     tion is used, in which case export	commands defining all 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]]
	     Fix command.  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 standard output, and -n inhibits the default
	     command numbers.  The -r option reverses the order	of the list.
	     Without -l, the selected commands are edited by the editor	speci-
	     fied with the -e option, or if no -e is specified,	the editor
	     specified by the FCEDIT parameter (if this	parameter is not set,
	     /bin/ed is	used), and then	executed by the	shell.

     fc	-s [-g]	[old=new] [prefix]
	     Re-execute	the most recent	command	beginning with prefix, or the
	     previous command if no prefix is specified, performing the	op-
	     tional substitution of old	with new.  If -g is specified, all oc-
	     currences of old are replaced with	new.  The editor is not	in-
	     voked when	the -s flag is used.  The obsolescent equivalent "-e
	     -"	is also	accepted.  This	command	is usually accessed with the
	     predefined	alias r='fc -s'.

     fg	[job ...]
	     Resume the	specified job(s) in the	foreground.  If	no jobs	are
	     specified,	%+ is assumed.	See Job	control	below for more infor-
	     mation.

     getopts optstring name [arg ...]
	     Used by shell procedures to parse the specified arguments (or po-
	     sitional parameters, if no	arguments are given) and to check for
	     legal options.  optstring contains	the option letters 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	char-
	     acter of the argument it is found in, the remainder of the	argu-
	     ment 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 argument	to be pro-
	     cessed by the next	call to	getopts	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 argu-
	     ment, getopts places it in	the shell parameter OPTARG.

	     When an illegal option or a missing option	argument is encoun-
	     tered, a question mark or a colon is placed in name (indicating
	     an	illegal	option or missing argument, respectively) and OPTARG
	     is	set to the option character that caused	the problem.  Further-
	     more, if optstring	does not begin with a colon, a question	mark
	     is	placed in name,	OPTARG is unset, and an	error message is
	     printed to	standard error.

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

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

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

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

     jobs [-lnp] [job ...]
	     Display information about the specified job(s); if	no jobs	are
	     specified,	all jobs are displayed.	 The -n	option causes informa-
	     tion 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 TERM signal 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 signal name corresponding to exit-status.  If no	argu-
	     ments are specified, 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 expressions may need to
	     be	quoted,	(( expr	)) is syntactic	sugar for let "expr".

     print [-nprsu[n] |	-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 inhib-
	     ited with the -r option.  The -s option prints to the history
	     file instead of standard output; the -u option prints to file de-
	     scriptor 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(1)
	     command, which does not process `\' sequences unless the -e op-
	     tion is given.  As	above, the -n option suppresses	the trailing
	     newline.

     pwd [-LP]
	     Print the present working directory.  If the -L option is used or
	     if	the physical option isn't set (see the set command below), the
	     logical path is printed (i.e. the path used to cd to the current
	     directory).  If the -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 [-prsu[n]] [parameter	...]
	     Reads a line of input from	the standard input, separates the line
	     into fields using the IFS parameter (see Substitution above), and
	     assigns 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 parameters,
	     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 the 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 ap-
	     pended to it, in which case the string is used as a prompt
	     (printed to standard error	before any input is read) if the input
	     is	a tty(4) (e.g. read nfoo?'number of foos: ').

	     The -un and -p options cause input	to be read from	file descrip-
	     tor n (n defaults to 0 if omitted)	or the current co-process (see
	     Co-processes above	for comments on	this), respectively.  If the
	     -s	option is used,	input is saved to the history file.

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

	     If	no parameters are specified, the names of all parameters with
	     the read-only attribute are printed one per line, unless the -p
	     option is used, in	which case readonly commands defining all
	     read-only 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 command
	     is	used.  If used outside of a function or	. script, it has the
	     same effect as exit.  Note	that ksh treats	both profile and ENV
	     files as .	scripts, while the original Korn shell only treats
	     profiles as . scripts.

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

	     -A	name	      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 ele-
			      ments are	set (where N is	the number of argu-
			      ments); the rest are left	untouched.

	     -a	| allexport   All new parameters are created with the export
			      attribute.

	     -b	| notify      Print job	notification messages asynchronously,
			      instead of just before the prompt.  Only used if
			      job control is enabled (-m).

	     -C	| noclobber   Prevent >	redirection from overwriting existing
			      files.  Instead, >| must be used to force	an
			      overwrite.

	     -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 ! statements.	For && or ||, only the status
			      of the last command is tested.

	     -f	| noglob      Do not expand file name patterns.

	     -h	| trackall    Create tracked aliases for all executed commands
			      (see Aliases above).  Enabled by default for
			      non-interactive shells.

	     -k	| keyword     Parameter	assignments are	recognized anywhere in
			      a	command.

	     -m	| monitor     Enable job control (default for interactive
			      shells).

	     -n	| noexec      Do not execute any commands.  Useful for check-
			      ing the syntax of	scripts	(ignored if interac-
			      tive).

	     -p	| privileged  The shell	is a privileged	shell.	It is set au-
			      tomatically if, when the shell starts, the real
			      UID or GID does not match	the effective UID
			      (EUID) or	GID (EGID), respectively.  See 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 with the set command it causes
			      the specified arguments to be sorted before as-
			      signing them to the positional parameters	(or to
			      array name, if -A	is used).

	     -u	| nounset     Referencing of an	unset parameter	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	| markdirs    Mark directories with a trailing `/' during file
			      name generation.

	     -x	| xtrace      Print commands and parameter assignments when
			      they are executed, preceded by the value of PS4.

	     bgnice	      Background jobs are run with lower priority.

	     braceexpand      Enable brace expansion (a.k.a. alternation).

	     csh-history      Enables a	subset of csh(1)-style history editing
			      using the	`!' character.

	     emacs	      Enable BRL emacs-like command-line editing (in-
			      teractive	shells only); see Emacs	editing	mode.

	     gmacs	      Enable gmacs-like	command-line editing (interac-
			      tive shells only).  Currently identical to emacs
			      editing except that transpose (^T) acts slightly
			      differently.

	     ignoreeof	      The shell	will not (easily) exit when end-of-
			      file is read; exit must be used.	To avoid infi-
			      nite loops, the shell will exit if EOF is	read
			      13 times in a row.

	     interactive      The shell	is an interactive shell.  This option
			      can only be used when the	shell is invoked.  See
			      above for	a description of what this means.

	     login	      The shell	is a login shell.  This	option can
			      only be used when	the shell is invoked.  See
			      above for	a description of what this means.

	     nohup	      Do not kill running jobs with a SIGHUP signal
			      when a login shell exits.	 Currently set by de-
			      fault; this is different from the	original Korn
			      shell (which doesn't have	this option, but does
			      send the SIGHUP 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" directories (i.e. the shell handles
			      `..', which allows the user to be	oblivious of
			      symbolic links to	directories).  Clear by	de-
			      fault.  Note that	setting	this option does not
			      affect 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.

	     restricted	      The shell	is a restricted	shell.	This option
			      can only be used when the	shell is invoked.  See
			      above for	a description of what this means.

	     sh		      Enable strict Bourne shell mode (see Strict
			      Bourne shell mode	above).

	     vi		      Enable vi(1)-like	command-line editing (interac-
			      tive shells only).

	     vi-esccomplete   In vi command-line editing, do command and 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,	characters in
			      the range	128-160	are printed as is, which may
			      cause problems.

	     vi-tabcomplete   In vi command-line editing, do command and file
			      name completion when tab (^I) is entered in in-
			      sert mode.  This is the default.

	     viraw	      No effect.  In the original Korn shell, unless
			      viraw was	set, the vi command-line mode would
			      let the tty(4) driver do the work	until ESC (^[)
			      was entered.  ksh	is always in viraw 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 cur-
	     rent shell	options	in a form that can be reinput to the shell to
	     achieve the same option settings.

	     Remaining arguments, if any, are positional parameters and	are
	     assigned, in order, to the	positional parameters (i.e. $1,	$2,
	     etc.).  If	options	end with `--' and there	are no remaining argu-
	     ments, all	positional parameters are cleared.  If no options or
	     arguments are given, the values of	all names are printed.	For
	     unknown historical	reasons, a lone	`-' option is treated spe-
	     cially - 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.

     suspend
	     Stops the shell as	if it had received the suspend character from
	     the terminal.  It is not possible to suspend a login shell	unless
	     the parent	process	is a member of the same	terminal session but
	     is	a member of a different	process	group.	As a general rule, if
	     the shell was started by another shell or via su(1), it can be
	     suspended.

     test expression
     [ expression ]
	     test evaluates the	expression and returns zero status if true, 1
	     if	false, or greater than 1 if there was an error.	 It is nor-
	     mally used	as the condition command of if and while statements.
	     Symbolic links are	followed for all file expressions except -h
	     and -L.

	     The following basic expressions are available:

	     -a	file		file exists.

	     -b	file		file is	a block	special	device.

	     -c	file		file is	a character special device.

	     -d	file		file is	a directory.

	     -e	file		file exists.

	     -f	file		file is	a regular file.

	     -G	file		file's group is	the shell's effective group
				ID.

	     -g	file		file's mode has	the setgid bit set.

	     -h	file		file is	a symbolic link.

	     -k	file		file's mode has	the sticky(8) bit set.

	     -L	file		file is	a symbolic link.

	     -O	file		file's owner is	the shell's effective user ID.

	     -o	option		Shell option is	set (see the set command above
				for a list of options).	 As a non-standard ex-
				tension, if the	option starts with a `!', the
				test is	negated; the test always fails if
				option doesn't exist (so [ -o foo -o -o	!foo ]
				returns	true if	and only if option foo ex-
				ists).

	     -p	file		file is	a named	pipe.

	     -r	file		file exists and	is readable.

	     -S	file		file is	a unix(4)-domain socket.

	     -s	file		file is	not empty.

	     -t	[fd]		File descriptor	fd is a	tty(4) device.	If the
				posix option is	not set, fd may	be left	out,
				in which case it is taken to be	1 (the behav-
				iour differs due to the	special	POSIX rules
				described above).

	     -u	file		file's mode has	the setuid bit set.

	     -w	file		file exists and	is writable.

	     -x	file		file exists and	is executable.

	     file1 -nt file2	file1 is newer than file2 or file1 exists and
				file2 does not.

	     file1 -ot file2	file1 is older than file2 or file2 exists and
				file1 does not.

	     file1 -ef file2	file1 is the same file as file2.

	     string		string has non-zero length.

	     -n	string		string is not empty.

	     -z	string		string is 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	prece-
	     dence over	binary operators, may be combined with the following
	     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).  For
	     example, [	-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 performed
	     (even if the first	argument is a unary operator, including	an un-
	     stripped `!').

	     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:

		   0m0.00s real	    0m0.00s user     0m0.00s system

	     If	the -p option is given the output is slightly longer:

		   real	    0.00
		   user	    0.00
		   sys	    0.00

	     It	is an error to specify the -p option unless pipeline is	a sim-
	     ple command.

	     Simple redirections of standard error do not affect 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 both by the
	     shell and by processes that the shell started which have exited.
	     The format	of the output is:

		   0m0.00s 0m0.00s
		   0m0.00s 0m0.00s

     trap [handler signal ...]
	     Sets a trap handler that is to be executed	when any of the	speci-
	     fied signals are received.	 handler is either a NULL string, in-
	     dicating the signals are to be ignored, a minus sign (`-'), indi-
	     cating that the default action is to be taken for the signals
	     (see signal(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
	     the 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 exe-
	     cuted after an error occurs (an error is something	that would
	     cause the shell to	exit if	the -e or errexit option were set -
	     see the set command above).  EXIT handlers	are executed in	the
	     environment of the	last executed command.	Note that for non-in-
	     teractive 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 cannot 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.

     type    Short form	of command -V (see above).

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

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

	     When -f is	used, typeset operates on the attributes of functions.
	     As	with parameters, if no name arguments 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.

	     -f	     Function mode.  Display or	set functions and their	at-
		     tributes, instead of parameters.

	     -i[n]   Integer attribute.	 n specifies the base to use when dis-
		     playing the integer (if not specified, the	base given in
		     the first assignment is used).  Parameters	with this at-
		     tribute may be assigned values containing arithmetic ex-
		     pressions.

	     -L[n]   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
		     whitespace	(and zeros, if used with the -Z	option)	is
		     stripped.	If necessary, values are either	truncated or
		     space padded to fit the field width.

	     -l	     Lower case	attribute.  All	upper case characters in val-
		     ues 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 com-
		     patibility).

	     -R[n]   Right 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.
		     Trailing whitespace is stripped.  If necessary, values
		     are either	stripped of leading characters or space	padded
		     to	make them fit the field	width.

	     -r	     Read-only attribute.  Parameters with this	attribute may
		     not be assigned to	or unset.  Once	this attribute is set,
		     it	cannot 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	     Unsigned integer attribute.  Integers are printed as un-
		     signed values (only useful	when combined with the -i op-
		     tion).  This option is not	in the original	Korn shell.

	     -u	     Upper case	attribute.  All	lower case characters in val-
		     ues 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 op-
		     tion.)

		     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 yet implemented.

	     -Z[n]   Zero fill attribute.  If not combined with	-L, this is
		     the same as -R, except zero padding is used instead of
		     space padding.

     ulimit [-acdfHlmnpSst [value]] ...
	     Display or	set process limits.  If	no options are used, the file
	     size limit	(-f) is	assumed.  value, if specified, may be either
	     an	arithmetic expression starting with a number or	the word
	     "unlimited".  The limits affect the shell and any processes cre-
	     ated by the shell after a limit is	imposed; limits	may not	be in-
	     creased once they are set.

	     -a	    Display all	limits;	unless -H is used, soft	limits are
		    displayed.

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

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

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

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

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

	     -m	n   Impose a limit of n	kilobytes on the amount	of physical
		    memory used.  This limit is	not enforced.

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

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

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

	     -s	n   Impose a size limit	of n kilobytes on the size of the
		    stack area.

	     -t	n   Impose a time limit	of n CPU seconds spent in user mode to
		    be used by each process.

	     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).  When 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).  For 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 "007".

     unalias [-adt] [name ...]
	     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 have the
	     read-only attribute set, 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 SIGHUP, SIGINT, or SIGQUIT signal	is re-
	     ceived.

	     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 is performed even	if name	is a
	     reserved word, alias, etc.	 Without the -v	option,	whence is sim-
	     ilar to command -v	except that whence 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	pipe-
     lines.  At	a minimum, the shell keeps track of the	status of the back-
     ground (i.e. asynchronous)	jobs that currently exist; this	information
     can be displayed using the	jobs commands.	If job control is fully	en-
     abled (using set -m or set	-o monitor), as	it is for interactive 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 back-
     ground using the fg and bg	commands, and the state	of the terminal	is
     saved or restored when a foreground job is	stopped	or restarted, respec-
     tively.

     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 the 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.

     %-		    The	job that would be the %+ job if	the latter did not ex-
		    ist.

     %n		    The	job with job number n.

     %?string	    The	job with its command containing	the string string (an
		    error occurs if multiple jobs are matched).

     %string	    The	job with its command starting with the 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 the `+' or `-'	character if the job is	the %+ or %- job, re-
	      spectively, or space if it is neither;

     status   indicates	the current state of the job and can be:

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

	      Running	 The job has neither stopped nor exited	(note that
			 running does not necessarily mean consuming CPU time
			 - the process could be	blocked	waiting	for some
			 event).

	      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); 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, 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 SIGHUP	signal and the shell exits.  Simi-
     larly, 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 SIGHUP signal and the shell exits.

   Interactive input line editing
     The shell supports	three modes of reading command lines from a tty(4) in
     an	interactive session, controlled	by the emacs, gmacs, and vi options
     (at most one of these can be set at once).	 The default is	emacs.	Edit-
     ing modes can be set explicitly using the set built-in, or	implicitly via
     the EDITOR	and VISUAL environment variables.  If none of these options
     are enabled, the shell simply reads lines using the normal	tty(4) 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 than the screen width (see
     the COLUMNS parameter), a `>', `+', or `<'	character is displayed in the
     last column 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 orig-
     inal Korn shell.  In this mode, various editing commands (typically bound
     to	one or more control characters)	cause immediate	actions	without	wait-
     ing for a newline.	 Several editing commands are bound to particular con-
     trol characters when the shell is invoked;	these bindings can be changed
     using the bind command.

     The following is a	list of	available editing commands.  Each description
     starts with the name of the command, suffixed with	a colon; an [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. the	ASCII ESC
     character is written as ^[.  ^[A-Z] sequences are not case	sensitive.  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 correspond-
     ing Emacs key bindings.  The user's tty(4)	characters (e.g. ERASE)	are
     bound to reasonable substitutes and override the default bindings.

     abort: ^C,	^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 or-
	     dinary characters are bound to this.

     backward-char: [n]	^B, ^X^D
	     Moves the cursor backward n characters.

     backward-word: [n]	^[b
	     Moves the cursor backward to the beginning	of the word; words
	     consist of	alphanumerics, underscore (`_'), and dollar sign (`$')
	     characters.

     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.

     clear-screen: ^L
	     Clears the	screen if the TERM parameter is	set and	the terminal
	     supports clearing the screen, then	reprints the prompt string and
	     the current input line.

     comment: ^[#
	     If	the current line does not begin	with a comment character, one
	     is	added at the beginning of the line and the line	is entered (as
	     if	return had been	pressed); otherwise, the existing comment
	     characters	are removed and	the cursor is placed at	the beginning
	     of	the line.

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

	     Custom completions	may be configured by creating an array named
	     `complete_command', optionally suffixed with an argument number
	     to	complete only for a single argument.  So defining an array
	     named `complete_kill' provides possible completions for any argu-
	     ment to the kill(1) command, but `complete_kill_1'	only completes
	     the first argument.  For example, the following command makes ksh
	     offer a selection of signal names for the first argument to
	     kill(1):

		   set -A complete_kill_1 -- -9	-HUP -INFO -KILL -TERM

     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 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: ^I,	^[=
	     Complete as much as is possible of	the current word, and list the
	     possible completions for it.  If only one completion is possible,
	     match as in the complete command above.

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

     delete-char-forward: [n] Delete
	     Deletes n characters after	the cursor.

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

     delete-word-forward: [n] ^[d
	     Deletes n words after the cursor.

     down-history: [n] ^N, ^XB
	     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-history
	     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, ^XC
	     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-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 indi-
	     cators 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.

     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:
	     Reprints the prompt string	and the	current	input line.

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

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

     search-history: ^R
	     Enter incremental search mode.  The internal history list is
	     searched backwards	for commands matching the input.  An initial
	     `^' in the	search string anchors the search.  The abort key will
	     leave search mode.	 Other commands	will be	executed after leaving
	     search mode.  Successive search-history commands continue search-
	     ing backward to the next previous occurrence of the pattern.  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.

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

     up-history: [n] ^P, ^XA
	     Scrolls the history buffer	backward n lines (earlier).

     upcase-word: [n] ^[U, ^[u
	     Uppercase the next	n words.

     quote: ^V
	     Synonym for ^^.

     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 previously killed	text string.

     The following editing commands lack default bindings but can be used with
     the bind command:

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

   Vi editing mode
     The vi command-line editor	in ksh has basically the same commands as the
     vi(1) editor 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> and	<esc>.

     +o	 The _ command is different (in	ksh it is the last argument command;
	 in vi(1) it goes to the start of the current line).

     +o	 The / and G commands move in the opposite direction to	the j command.

     +o	 Commands which	don't make sense in a single line editor are not
	 available (e.g. screen	movement commands and ex(1)-style colon	(:)
	 commands).

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

     Like vi(1), there are two modes: "insert" mode and	"command" mode.	 In
     insert mode, most characters are simply put in the	buffer at the current
     cursor position as	they are typed;	however, some characters are treated
     specially.	 In particular,	the following characters are taken from	cur-
     rent tty(4) 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	char-
     acters are	also treated specially in insert mode:

     ^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.

     ^H		 Erases	previous character.

     ^J	| ^M	 End of	line.  The current line	is read, parsed, and executed
		 by the	shell.

     ^V		 Literal next.	The next character typed is not	treated	spe-
		 cially	(can be	used to	insert the characters being described
		 here).

     ^X		 Command and file name expansion (see below).

     <esc>	 Puts the editor in command mode (see below).

     <tab>	 Optional file name and	command	completion (see	^F above), en-
		 abled with set	-o vi-tabcomplete.

     In	command	mode, each character is	interpreted as a command.  Characters
     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 fol-
     lowing command descriptions, an [n] indicates the command may be prefixed
     by	a number (e.g. 10l moves right 10 characters); if no number 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 letters, digits, and un-
     derscore characters or a sequence of non-letter, non-digit, non-under-
     score, and	non-whitespace characters (e.g.	"ab2*&^" contains two words)
     and a "big-word" is a sequence of non-whitespace 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 in-
		 sert 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).

     [n]g	 Like G, except	if n is	not specified, it goes to the most re-
		 cent remembered line.

     [n]v	 Edit line n using the vi(1) 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 glob-
		 bing characters) - the	big-word is replaced with the result-
		 ing words.  If	the current big-word is	the first on the line
		 or follows one	of the characters `;', `|', `&', `(', or `)',
		 and does not contain a	slash (`/'), then command expansion is
		 done; otherwise file name expansion is	done.  Command expan-
		 sion 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 performing com-
		 mand and file name expansion.	<tab> is only recognized if
		 the vi-tabcomplete option is set, while <esc> is only recog-
		 nized if the vi-esccomplete option is set (see	set -o).  If n
		 is specified, the nth possible	completion is selected (as re-
		 ported	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.

     @c		 Macro expansion.  Execute the commands	found in the alias _c.

     Intra-line	movement commands:

     [n]h and [n]^H
	     Move left n characters.

     [n]l and [n]<space>
	     Move right	n characters.

     0	     Move to column 0.

     ^	     Move to the first non-whitespace character.

     [n]|    Move to column n.

     $	     Move to the last character.

     [n]b    Move back n words.

     [n]B    Move back n big-words.

     [n]e    Move forward to the end of	the word, n times.

     [n]E    Move forward to the end of	the big-word, n	times.

     [n]w    Move forward n words.

     [n]W    Move forward n big-words.

     %	     Find match.  The editor looks forward for the nearest parenthe-
	     sis, bracket, or brace and	then moves the cursor to the matching
	     parenthesis, bracket, or brace.

     [n]fc   Move forward to the nth occurrence	of the character c.

     [n]Fc   Move backward to the nth occurrence of the	character c.

     [n]tc   Move forward to just before the nth occurrence of the character
	     c.

     [n]Tc   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:

     [n]j, [n]+, and [n]^N
	     Move to the nth next line in the history.

     [n]k, [n]-, and [n]^P
	     Move to the nth previous line in the history.

     [n]G    Move to line n in the history; if n is not	specified, the number
	     of	the first remembered line is used.

     [n]g    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 containing
	     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 history.

     [n]n    Search for	the nth	occurrence of the last search string; the di-
	     rection of	the search is the same as the last search.

     [n]N    Search for	the nth	occurrence of the last search string; the di-
	     rection of	the search is the opposite of the last search.

     Edit commands

     [n]a    Append text n times; goes into insert mode	just after the current
	     position.	The append is only replicated if command mode is re-
	     entered i.e. <esc>	is used.

     [n]A    Same as a,	except it appends at the end of	the line.

     [n]i    Insert text n times; goes into insert mode	at the current posi-
	     tion.  The	insertion is only replicated if	command	mode is	re-en-
	     tered i.e.	<esc> is used.

     [n]I    Same as i,	except the insertion is	done just before the first
	     non-blank character.

     [n]s    Substitute	the next n characters (i.e. delete the characters and
	     go	into insert mode).

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

     [n]cmove-cmd
	     Change from the current position to the position resulting	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).

     [n]x    Delete the	next n characters.

     [n]X    Delete the	previous n characters.

     D	     Delete to the end of the line.

     [n]dmove-cmd
	     Delete from the current position to the position resulting	from n
	     move-cmds;	move-cmd is a movement command (see above) or d, in
	     which case	the current line is deleted.

     [n]rc   Replace the next n	characters with	the character c.

     [n]R    Replace.  Enter insert mode but overwrite existing	characters in-
	     stead of inserting	before existing	characters.  The replacement
	     is	repeated n times.

     [n]~    Change the	case of	the next n characters.

     [n]ymove-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.

     [n]p    Paste the contents	of the yank buffer just	after the current po-
	     sition, n times.

     [n]P    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 current line
	     to	be deleted and a new prompt to be printed.

FILES
     ~/.profile		  User's login profile.
     /etc/ksh.kshrc	  Global configuration file.  Not sourced by default.
     /etc/profile	  System login profile.
     /etc/shells	  Shell	database.
     /etc/suid_profile	  Privileged shell profile.

SEE ALSO
     csh(1), ed(1), mg(1), sh(1), stty(1), vi(1), shells(5), environ(7),
     script(7)

     Morris Bolsky and David Korn, The KornShell Command and Programming
     Language, 2nd Edition, Prentice Hall, 1995, ISBN 0131827006.

     Stephen G.	Kochan and Patrick H. Wood, UNIX Shell Programming, 3rd
     Edition, Sams, 2003, ISBN 0672324903.

     IEEE Inc.,	IEEE Standard for Information Technology - Portable Operating
     System Interface (POSIX) -	Part 2:	Shell and Utilities, 1993, ISBN
     1-55937-266-9.

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 subsequently
     maintained	by John	R. MacMillan <change!john@sq.sq.com>, Simon J. Gerraty
     <sjg@zen.void.oz.au>, and 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.

BUGS
     $(command)	expressions are	currently parsed by finding the	closest	match-
     ing (unquoted) parenthesis.  Thus constructs inside $(command) may	pro-
     duce an error.  For example, the parenthesis in `x);;' is interpreted as
     the closing parenthesis in	`$(case	x in x);; *);; esac)'.

BSD				 April 3, 2019				   BSD

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

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