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GETOPT(1)		     General Commands Manual		       GETOPT(1)

NAME
     getopt -- parse command options

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

DESCRIPTION
     The  getopt  utility  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 fol-
     lowed 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.  The getopt utility will place `--'
     in the arguments at the end of the options, or recognize it if used explic-
     itly.  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.

EXIT STATUS
     The getopt utility prints an error message on the standard error output and
     exits with status > 0 when it encounters an option letter not  included  in
     optstring.

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 re-
     quires 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 [ $? -ne 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.
	   while :; do
		   case "$1" in
		   -a|-b)
			   echo "flag $1 set"; sflags="${1#-}$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 file1 file2
	   cmd -a -o arg file1 file2
	   cmd -oarg -a file1 file2
	   cmd -a -oarg -- file1 file2

SEE ALSO
     getopts(1), sh(1), getopt(3)

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

BUGS
     Whatever getopt(3) has.

     Arguments containing white space or embedded shell metacharacters generally
     will  not survive intact; this looks easy to fix but is not.  People trying
     to fix getopt or the example in this manpage should check	the  history  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  cor-
     rectly  (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 ports 15.quarterly	 August 1, 2015 		       GETOPT(1)

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