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NetBSD 6.1.5 - man page for getopt (netbsd section 1)

GETOPT(1)			   BSD General Commands Manual				GETOPT(1)

     getopt -- parse command options

     args=`getopt optstring $*`

     set -- `getopt optstring $*`

     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.

     getopt should not be used in new scripts; use the shell builtin getopts instead.

     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 [c], which requires an argument.

	   args=`getopt abc: $*`
	   if [ $? -ne 0 ]; then
		   echo 'Usage: ...'
		   exit 2
	   set -- $args
	   while [ $# -gt 0 ]; do
		   case "$1" in
				   carg=$2; shift
				   shift; break

     This code will accept any of the following as equivalent:

	   cmd -acarg file file
	   cmd -a -c arg file file
	   cmd -carg -a file file
	   cmd -a -carg -- file file

     IEEE Std 1003.2 (``POSIX.2'') mandates that the sh(1) set command return the value of 0 for
     the exit status.  Therefore, the exit status of the getopt command is lost when getopt and
     the sh(1) set command are used on the same line.  The example given is one way to detect
     errors found by getopt.

     getopt prints an error message on the standard error output when it encounters an option
     letter not included in [optstring].

     sh(1), getopt(3)

     Written by Henry Spencer, working from a Bell Labs manual page.  Behavior believed identical
     to the Bell version.

     Whatever getopt(3) has.

     Arguments containing white space or embedded shell metacharacters generally will not survive
     intact;  this looks easy to fix but isn't.

     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.

BSD					November 28, 2009				      BSD

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