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getopt(1) [ultrix man page]

getopt(1)						      General Commands Manual							 getopt(1)

Name
       getopt - parse command options

Syntax
       set - - getopt optstring $*

Description
       The  command  breaks  up  options in command lines for easy parsing by Shell procedures and checks for legal options.  The optstring option
       letters are recognized if a letter is followed by a colon, the option expects an argument which may or may not  be  separated  from  it	by
       white space.  For further information, see

       The special option, specified by two minus signs (- -), delimits the end of the options.  If the delimiters are used explicitly, recognizes
       it; otherwise, generates it.  In either case, places the delimiter at the end of the options.  The positional parameters ($1 $2 ...) of the
       shell  are reset so that each option is preceded by a single minus sign (-) and is in its own positional parameter; each option argument is
       also parsed into its own positional parameter.

Examples
       The following code fragment shows how you can process the arguments for a command that can take the options a or b, as well as  the  option
       o, which requires an argument:
       #!/bin/sh5
       set -- getopt abo: $*
       if [ $? != 0 ]
       then
	    echo $USAGE
	    exit 2
       fi
       for i in $*
       do
	    case $i in
	    -a | -b)  FLAG=$i; shift;;
	    -o)  OARG=$2; shift 2;;
	    --)  shift; break;;
	    esac
       done
       This code accepts 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

Diagnostics
       The command prints an error message on the standard error when it encounters an option letter not included in optstring.

See Also
       sh5(1), getopt(3)

																	 getopt(1)

Check Out this Related Man Page

GETOPT(1)						    BSD 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 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. The getopt utility 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 argu- ment. 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 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 [ $? -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 true; 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 file file cmd -a -o arg file file cmd -oarg -a file file cmd -a -oarg -- file file 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. Peo- ple 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 ver- sion to another. Each shellscript has to carry complex code to parse arguments halfway correctly (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. BSD
January 26, 2011 BSD
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