Simple Bash Shell Command Line Processing Template

parseflags.sh

#!/bin/bash
#
# Self-contained command line processing in bash that supports the
# minimal, lowest common denominator compatibility of flag parsing.

# -u: undefined variables is an error
# -e: exit shell on error
set -eu

function usage() {
    echo "Usage: parseflags.sh [--help|-h] [--binary] [--option opt] [--] \
files..."
    exit 1
}

binary=0
option=''
while [[ $# -gt 0 ]]; do
    case $1 in
        --binary) binary=1 ;;
        --option) shift; option="$1" ;;
        --help|-h) usage ;;
        --) shift; break ;;
        -*) echo "Unknown flag '$1'" 1>&2; usage 1>&2 ;;
        *) break ;;
    esac
    shift
done

echo "binary=$binary"
echo "option=$option"
echo "files: $@"