getopts and mandatory arguments in BASH

jmcejuela · 04-03-2009, 03:28 PM

Hi there,

I am writting a script and I want some optional arguments for what I use getopts, and a mandatory argument, so the usage of the script is:

script [OPTIONS] mandatory

How to reference the mandatory argument? I mean, in which variable is stored, $n ? After running getopts can I have an index or something like that?

Thanks for your time.

dwhitney67 · 04-03-2009, 03:42 PM

As the thread title implies, getopt is the way to go. Here's a simple example:

Code:

#!/bin/bash

set -e

OPTS=`getopt -n $0 -o p:h: --long port:,host: -- $@`

eval set -- "$OPTS"

while true
do
        case "$1" in
                -p|--port)  echo "port = $2"; shift 2 ;;
                -h|--host)  echo "host = $2"; shift 2 ;;
                --)         shift ; break ;;
        esac
done

Here, both -p (or --port) and -h (or --host) require one to input values; the ':' that is placed after the options p and h above, imply this. If an arg is not required, then don't use the ':' after the option.

jmcejuela · 04-03-2009, 03:54 PM

hmm I want it more easy. I have discovered that it is the OPTIND variable which is the index I was looking for, how to do something like ${$OPTIND} to reference to the bash variable that reference to the $OPTIND th argument?

danke!

jmcejuela · 04-03-2009, 04:00 PM

oh yeah, it´s simple done with shift.

Thank you so much.