GETOPT(1)
NAME
getopt - parse command options
SYNOPSIS
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 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. 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.
EXAMPLE
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.
set -- `getopt abo: $*`
if test $? != 0
then
echo 'Usage: ...'
exit 2
fi
for i
do
case "$i"
in
-a|-b)
flag=$i; shift;;
-o)
oarg=$2; shift; shift;;
--)
shift; break;;
esac
done
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
Getopt prints an error message on the standard error output when it en-
counters 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.
BUGS
Whatever getopt(3) has.
Arguments containing white space or imbedded shell metacharacters gener-
ally 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. varies from one shell version to another.