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getopt(1) [osx 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. 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
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. 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 isn't. 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 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. BSD
April 3, 1999 BSD

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getopt(1)						      General Commands Manual							 getopt(1)

NAME
getopt - parse command options SYNOPSIS
optstring args DESCRIPTION
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(3C)). 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 whitespace. The positional parameters ...) of the shell are reset so that each option is preceded by a and is in its own positional parameter; each option argument is also parsed into its own positional parameter. recognizes two hyphens to delimit the end of the options. If absent, places at the end of the options. The most common use of is in the shell's command (see the example below) where converts the command line to a more easily parsed form. writes the modified command line to the standard output. EXTERNAL INFLUENCES
Environment Variables determines the language in which messages are displayed. If is not specified in the environment or is set to the empty string, the value of is used as a default for each unspecified or empty vari- able. If is not specified or is set to the empty string, a default of "C" (see lang(5)) is used instead of If any internationalization variable contains an invalid setting, behaves as if all internationalization variables are set to "C". See environ(5). International Code Set Support Single-byte and multibyte character code sets are supported. DIAGNOSTICS
prints an error message on the standard error when it encounters an option letter that is not included in optstring. EXAMPLES
The following code fragment processes the arguments for a command that can take the options or and the option which requires an argument: This code accepts any of the following as equivalent: WARNINGS
option arguments must not be null strings nor contain embedded blanks. SEE ALSO
getopts(1), sh(1), getopt(3C). getopt(1)
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