A bash template with argument parsing and error handling

bash_template.sh

#!/bin/bash
# my bash template
set -o errexit
set -o nounset
shopt -s nullglob

SCRIPT_PATH="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd -P)"

function die() {
    echo "ERROR $? IN ${BASH_SOURCE[0]} AT LINE ${BASH_LINENO[0]}" 1>&2
    exit 1
}
trap die ERR

function usage() {
    cat <<EOF
Usage ${SCRIPT_PATH}/$0 OPTIONS
Options:
    --version=N  sets the version
    -d           start in daemon mode
    --help, -h   this help
EOF
}

# parse arguments
version=""
daemon=0
args=()
while [[ $# -gt 0 ]]; do
    case "$1" in
    -v=* | --version=*)
        # set an option with argument
        version="${1#*=}"
        ;;

    -d | --daemon)
        # set a binary option
        daemon=1
        ;;

    -h | --help)
        usage
        exit 0
        ;;

    --)
        # forward all arguments after `--` to the command
        shift
        args+=("${@}")
        break
        ;;
    *)
        echo "ERROR: unknown option '$1'"
        usage
        exit 1
        ;;
    esac
    shift
done

# OK do here something with "${args[@]}"
echo "SCRIPT_PATH = ${SCRIPT_PATH}"
echo "args    = ${args[*]:-}"
echo "version = $version"
echo "daemon  = $daemon"