Bash menu with multiple parameters in one row

Question

I have searched a couple of days and still didn't found the answer. I hope that you can point me in right direction.

I would like to know how to write a bash script with a options, that can be called in one row, such as: script.sh -a -b -c. Parameters which aren't chosen are ignored.

Menu/options should be like:

-a description: something -b description: something else -c description: something different -d description: something.. 

is there any way to do this?

Answer 1

The usual way of handling switches and arguments is with the getopts function. In bash this is a builtin and you can find information about it in the bash man page (man bash).

Essentially, you declare a string that tells getopts what parameters to expect, and whether they should have an argument. It's getopts that handles bunched parameters (eg -abc being equivalent to -a -b -c) and the parsing of the command line. At the end of the getopts processing you have the remainder of the command line to handle as you see fit.

A typical script segment could look something like this

ARG_A= FLAG_B= FLAG_C= while getopts 'a:bc' OPT # -a {argument}, -b, -c do case "$OPT" in a) ARG_A="$OPTARG" ;; b) FLAG_B=yes ;; c) FLAG_C=yes ;; *) echo "ERROR: the options are -a {arg}, -b, -c" >&2; exit 1 ;; esac done shift $(($OPTIND - 1)) echo "Remaining command line: $*" 

You can add ? as a command option if you want a nice usage message. Remember that in the case block you would need to quote it or prefix it with a backslash so it's treated as a literal.

If you're wanting to run this under a different shell that doesn't have the builtin, or if you want to use long arguments such as --verbose instead of just -v take a look at the getopt utility. This is not a builtin but has been written to deliver in the more sophisticated situation.

Answer 2

You don't have to use any Bash-specific features to do this:

#!/bin/sh while true do case "$1" in -a) echo Saw -a! ;; -b) echo Saw -b! ;; -c) echo Saw -c! ;; -?) cat <<USAGE usage: $0 [-a] [-b] [-c] args You cannot currently combine options, as with -ac. USAGE exit 1 ;; *) echo End of options! break; ;; esac shift # toss current $1; we're done with it now done for p in "$@" do echo "Non-option argument: '$p'" done 

Unlike the code in roaima's answer, mine is portable shell script code. It will run on any Bourne type Unix shell going back to about 1980 or so.

I think the -? handler answers your "menu" requirement. The <<USAGE construct is called a heredoc.