Bash argument parsing with 'set -euo pipefail'

bash-arg-parsing.sh

#!/usr/bin/env bash

# https://web.archive.org/web/20190329060125/https://vaneyckt.io/posts/safer_bash_scripts_with_set_euxo_pipefail/
set -euo pipefail

# Set default values for mandatory arguments
CLONE_URL=''
BRANCH_NAME=''

print_help() {
  cat <<HELP
Usage: $0 --clone-url <clone_url> --branch <branch_name>
Deploy app from Git repository.

  --clone-url  URL to clone Git repository
  --branch     Branch name to check out
HELP
}

# Loop through all arguments
while [[ -n "${1-}" ]]; do
  case "$1" in
    --clone-url)
      shift
      CLONE_URL="${1-}" # Use default value '' if switch is passed with no value
      ;;
    --branch)
      shift
      BRANCH_NAME="${1-}"
      ;;
    --help)
      print_help
      exit 0
      ;;
    *)
      echo "Unknown argument: $1"
      print_help
      exit 1
      ;;
  esac
  shift || true # Do not fail the script if there are no arguments left
done

if [[ -z "$CLONE_URL" ]] || [[ -z "$BRANCH" ]]; then
  echo "Not all mandatory arguments were passed"
  print_help
  exit 2
fi

# The rest of the script goes here