bash_template

#!/usr/bin/env bash	
#
# Features:
# 
#  Mmodern Bash syntax
#  Using funtions
#  Support "--help"
#  Read username and password
#  Clean up afterwards
#
# General References:
#   - Cheatsheet: https://devhints.io/bash
#   - Bash Guide: mywiki.wooledge.org/BashGuide
#   - Style Guide: https://github.com/progrium/bashstyle
#   - Best practice: https://sap1ens.com/blog/2017/07/01/bash-scripting-best-practices/
#   - Write idempotent code: https://arslan.io/2019/07/03/how-to-write-idempotent-bash-scripts/
#


# Code by https://bertvv.github.io/cheat-sheets/Bash.html
set -o errexit   # Abort on nonzero exitstatus
set -o nounset   # Abort on unbound variable
set -o pipefail  # Don't hide errors within pipes

# Code by https://kvz.io/bash-best-practices.html
readonly __dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
readonly __file="${__dir}/$(basename "${BASH_SOURCE[0]}")"
readonly __base="$(basename "${__file}")"
readonly __root="$(cd "$(dirname "${__dir}")" && pwd)" # <-- change this as it depends on your app

clean_up () {

   local result=$?
   # Add clean-up code here.
   exit "${result}"

}
trap "clean_up" EXIT ERR

help () {

   printf    "\nUsage: %s [--username|-u <name> [--password|-p <password>]] [--help]" "${__base}"
   printf -- "\n\n\tBrief description"
   printf -- "\n\n"
   printf    "\tRoot directory: %s\n\n" "${__root}"

}

is_empty () {

   local string="${1}"
   [[ -z "${string}" ]]

}


main() {

   local username=""
   local password=""


   # Parse command line
   while [ $# -gt 0 ]; do
       case "${1}" in
         --help)
             help >&2
             exit 1
             ;;
         --username | -u)
              username="${2}"; shift
             ;;
         --password | -p)
             password="${2}"; shift
             ;;
         -*)
             {
                printf "Error: Unknown option: %s" "${1}"
                help
             } >&2
             exit 2
             ;;
         *)  break
             ;;
       esac
       shift
   done

if is_empty "${username}"; then
   printf -- "\nUsername: "; read -r username
   if is_empty "${password}"; then
      printf -- "\nPassword: "; read -r -s password 
   fi
fi
   
}

main "${@}"