bash tool boilerplate

bash_tool_skeleton.sh

#!/bin/bash
# Bash script with subcommands and options
# Licence: MIT
# Based on 
# - http://stackoverflow.com/questions/13638248/sub-commands-with-bash
# - http://wiki.bash-hackers.org/howto/getopts_tutorial

help() {
  echo "Help: valid commands: install, apply, setup, help" >&2
}

install() {
  while getopts :m: opt "$@"; do
    case $opt in
      m)
        echo "Set install mode: $OPTARG" >&2
        ;;
      \?)
        echo "Invalid install option: -$OPTARG" >&2
        exit 1
        ;;
      :)
        echo "Installation mode -$OPTARG requires an argument." >&2
        exit 1
        ;;
    esac
  done
  echo "installing"
}

apply() {
  shift $((OPTIND - 1))
  echo "run apply $@"
}

setup() {
  shift $((OPTIND - 1))
  install
  apply "$@"
}

# demo
args() {
  printf "%s" options:
  while getopts a:b:c:d:e:f:g:h:i:j:k:l:m:n:o:p:q:r:s:t:u:v:w:x:y:z: OPTION "$@"; do
    printf " -%s '%s'" $OPTION $OPTARG
  done
  shift $((OPTIND - 1))
  printf "\narg: '%s'" "$@"
  echo
}

if [[ $1 =~ ^(install|apply|help|args)$ ]]; then
  "$@"
else
  help
  echo "first arg '$1' is not a valid command, passing all options to setup" >&2
  setup "$@"
  #  echo "Invalid subcommand $1" >&2
  #  exit 1
fi