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GETOPT(1)		FreeBSD	General	Commands Manual		     GETOPT(1)

NAME
     getopt -- parse command options

SYNOPSIS
     args=`getopt optstring $*`	; errcode=$?; set -- $args

DESCRIPTION
     Getopt is used to break up	options	in command lines for easy parsing by
     shell procedures, and to check for	legal options.	Optstring is a string
     of	recognized option letters (see getopt(3)); if a	letter is followed by
     a colon, the option is expected to	have an	argument which may or may not
     be	separated from it by white space.  The special option `--' is used to
     delimit the end of	the options.  Getopt will place	`--' in	the arguments
     at	the end	of the options,	or recognize it	if used	explicitly.  The shell
     arguments ($1 $2 ...) are reset so	that each option is preceded by	a `-'
     and in its	own shell argument; each option	argument is also in its	own
     shell argument.

EXAMPLES
     The following code	fragment shows how one might process the arguments for
     a command that can	take the options -a and	-b, and	the option -o, which
     requires an argument.

	   args=`getopt	abo: $*`
	   # you should	not use	`getopt	abo: "$@"` since that would parse
	   # the arguments differently from what the set command below does.
	   if [	$? != 0	]
	   then
		   echo	'Usage:	...'
		   exit	2
	   fi
	   set -- $args
	   # You cannot	use the	set command with a backquoted getopt directly,
	   # since the exit code from getopt would be shadowed by those	of set,
	   # which is zero by definition.
	   for i
	   do
		   case	"$i"
		   in
			   -a|-b)
				   echo	flag $i	set; sflags="${i#-}$sflags";
				   shift;;
			   -o)
				   echo	oarg is	"'"$2"'"; oarg="$2"; shift;
				   shift;;
			   --)
				   shift; break;;
		   esac
	   done
	   echo	single-char flags: "'"$sflags"'"
	   echo	oarg is	"'"$oarg"'"

     This code will accept any of the following	as equivalent:

	   cmd -aoarg file file
	   cmd -a -o arg file file
	   cmd -oarg -a	file file
	   cmd -a -oarg	-- file	file

SEE ALSO
     sh(1), getopt(3)

DIAGNOSTICS
     Getopt prints an error message on the standard error output and exits
     with status > 0 when it encounters	an option letter not included in
     optstring.

HISTORY
     Written by	Henry Spencer, working from a Bell Labs	manual page.  Behavior
     believed identical	to the Bell version.  Example changed in FreeBSD ver-
     sion 3.2 and 4.0.

BUGS
     Whatever getopt(3)	has.

     Arguments containing white	space or embedded shell	metacharacters gener-
     ally will not survive intact;  this looks easy to fix but isn't. People
     trying to fix getopt or the example in this manpage should	check the his-
     tory of this file in FreeBSD.

     The error message for an invalid option is	identified as coming from
     getopt rather than	from the shell procedure containing the	invocation of
     getopt; this again	is hard	to fix.

     The precise best way to use the set command to set	the arguments without
     disrupting	the value(s) of	shell options varies from one shell version to
     another.

     Each shellscript has to carry complex code	to parse arguments halfway
     correcty (like the	example	presented here). A better getopt-like tool
     would move	much of	the complexity into the	tool and keep the client shell
     scripts simpler.

FreeBSD	10.1			 April 3, 1999			  FreeBSD 10.1

NAME | SYNOPSIS | DESCRIPTION | EXAMPLES | SEE ALSO | DIAGNOSTICS | HISTORY | BUGS

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