GETOPT(1) OpenBSD Reference Manual GETOPT(1)NAMEgetopt - parse command options
SYNOPSIS
args=`getopt optstring $*`; set -- $args
DESCRIPTIONgetopt 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 whitespace. However, if a letter is
followed by two colons, the argument is optional and may not be separated
by whitespace - this is an extension not covered by POSIX. 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.
Note that the construction set -- `getopt optstring $*` is not
recommended, as the exit value from ``set'' will prevent the exit value
from getopt from being determined.
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: $*`
if [ $? -ne 0 ]
then
echo 'Usage: ...'
exit 2
fi
set -- $args
while [ $# -ge 0 ]
do
case "$1"
in
-a|-b)
flag="$1"; 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
DIAGNOSTICSgetopt prints an error message on the standard error output when it
encounters an option letter not included in [optstring].
SEE ALSOsh(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 whitespace 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.
OpenBSD 4.9 October 28, 2010 OpenBSD 4.9