getopt(1) [netbsd man page]

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

NAME

     getopt -- parse command options

SYNOPSIS

     args=`getopt optstring $*`

     set -- `getopt optstring $*`

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.

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

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
     [c], which requires an argument.

	   args=`getopt abc: $*`
	   if [ $? -ne 0 ]; then
		   echo 'Usage: ...'
		   exit 2
	   fi
	   set -- $args
	   while [ $# -gt 0 ]; do
		   case "$1" in
			   -a|-b)
				   flag=$1
				   ;;
			   -c)
				   carg=$2; shift
				   ;;
			   --)
				   shift; break
				   ;;
		   esac
		   shift
	   done

     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.

DIAGNOSTICS

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

SEE ALSO

     sh(1), getopt(3)

HISTORY

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

BUGS

     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 ver-
     sion to another.

BSD
								 November 28, 2009							       BSD

GETOPT(3)						     Library Functions Manual							 GETOPT(3)

NAME

       getopt - get option letter from argv

SYNOPSIS

       int getopt(argc, argv, optstring)
       int argc;
       char **argv;
       char *optstring;

       extern char *optarg;
       extern int optind;

DESCRIPTION

       Getopt returns the next option letter in argv that matches a letter in optstring.  Optstring is a string of recognized option letters; if a
       letter is followed by a colon, the option is expected to have an argument that may or may not be separated from it by white space.   Optarg
       is set to point to the start of the option argument on return from getopt.

       Getopt  places  in  optind  the argv index of the next argument to be processed.  Because optind is external, it is normally initialized to
       zero automatically before the first call to getopt.

       When all options have been processed (i.e., up to the first non-option argument), getopt returns EOF.  The special option -- may be used to
       delimit the end of the options; EOF will be returned, and -- will be skipped.

DIAGNOSTICS

       Getopt prints an error message on stderr and returns a question mark (?)  when it encounters an option letter not included in optstring.

EXAMPLE

       The  following  code fragment shows how one might process the arguments for a command that can take the mutually exclusive options a and b,
       and the options f and o, both of which require arguments:

	      main(argc, argv)
	      int argc;
	      char **argv;
	      {
		   int c;
		   extern int optind;
		   extern char *optarg;
		   .
		   .
		   .
		   while ((c = getopt(argc, argv, "abf:o:")) != EOF)
			switch (c) {
			case `a':
			     if (bflg)
				  errflg++;
			     else
				  aflg++;
			     break;
			case `b':
			     if (aflg)
				  errflg++;
			     else
				  bproc();
			     break;
			case `f':
			     ifile = optarg;
			     break;
			case `o':
			     ofile = optarg;
			     break;
			case `?':
			default:
			     errflg++;
			     break;
			}
		   if (errflg) {
			fprintf(stderr, "Usage: ...");
			exit(2);
		   }
		   for (; optind < argc; optind++) {
			.
			.
			.
		   }
		   .
		   .
		   .
	      }

HISTORY

       Written by Henry Spencer, working from a Bell Labs manual page.	Modified by Keith Bostic to behave more like the System V version.

BUGS

       It is not obvious how `-' standing alone should be treated;  this version treats it as a non-option argument, which is not always right.

       Option arguments are allowed to begin with `-'; this is reasonable but reduces the amount of error checking possible.

       Getopt is quite flexible but the obvious price must be paid:  there is much it could do that it doesn't, like checking  mutually  exclusive
       options, checking type of option arguments, etc.

4.3 Berkeley Distribution					   May 27, 1986 							 GETOPT(3)