Sample bash script

sample_script.sh

#!/usr/bin/env bash

################################################################################
##  File:  script.sh
##  Desc:  Sample bash argument processing
##  Author: Nilson Lopes <[email protected]>
################################################################################

set -o nounset

PROGRAM_NAME=$(basename "$0")
LOGFILE="/tmp/$(date +%Y%m%d-%H%M).log"
VERSION="1.0"
SERIAL=0

# Check for root.
if (($(id -u) != 0)); then
    echo "This script must be run with root privileges."
    exit 1
fi

function usage() {
    cat <<EOF
${PROGRAM_NAME} - Version ${VERSION}

Usage: ${PROGRAM_NAME} [OPTIONS] ...
  -s, --serial       System Serial Number.
  -h, --help         Display this help menu.
EOF
}

function parse_arguments() {
    local -r SHORT_OPTIONS="hs:"
    local -r LONG_OPTIONS="help,serial:"

    if [ $# -eq 0 ]; then
        usage
        exit 1
    fi

    # Parse arguments
    if ! OPTIONS=$(getopt -o "$SHORT_OPTIONS" --long "$LONG_OPTIONS" -n "$PROGRAM_NAME" -- "$@"); then
        usage
        exit 1
    fi

    eval set -- "$OPTIONS"

    while true; do
        case "$1" in
        -s | --serial)
            SERIAL="$2"
            shift 2
            ;;
        -h | --help)
            usage
            exit 0
            ;;
        --)
            shift
            break
            ;;
        *)
            echo "Internal error!"
            exit 1
            ;;
        esac
    done
}

# command line parsing
parse_arguments "$@"

# start logging
exec \
    3>&1 \
    4>&2 \
    5>>"$LOGFILE" \
    > >(tee -a "$LOGFILE") \
    2> >(tee -a "$LOGFILE" >&2)

# add your logic here
echo "$SERIAL"