Questions tagged [getopts]

getopts is a shell builtin for parsing command-line options of the form -a where a is a letter or other character. It is available in all Bourne-style shells (Bourne, ash, bash, dash, ksh, zsh, ...) and defined by the POSIX standard.

Using getopts usually involves using a loop calling getopts OPTSTRING varname, in which each call to getopts will parse the next option, set varname with the option name and return success.

Example

#!/bin/sh

while getopts a:b flag
do
    case $flag in
        a) echo "a flag used, with value $OPTARG" ;;
        b) echo "b flag used" ;;
        ?) echo "Usage: PROGRAM [-a ARG1] [-b]"; exit 1 ;;
    esac
done
shift $((OPTIND - 1)) # remove parsed args from the arglist
echo remaining args: $*

Documentation

• Single Unix v3
• bash manual