template

#!/bin/bash
# Script template for my bash projects

# Constants
DEBUG=1
VERBOSE=0

# Functions
err() { printf "$0[error]: %s\n" "$*" >&2; exit 2; }
debug() { ((DEBUG)) && printf "$0[debug]: %s\n" "$*" >&2; }
verbose() { ((VERBOSE)) && printf "$0[info:] %s\n" "$*" >&2; }
help() { printf '%s\n' "
Usage:  $0 [-v] [-o arg] arg...
        $0 -h
        
        -v      ...verbose
        -o arg  ...option with argument
        -h      ...this help
"; }

# Test options
while getopts 'hvo:' opt; do
  case $opt in
    h) help; exit 0;;
    v) ((VERBOSE++));;
    o) OPTION_ARGUMENT="${OPTARG}";;
   \?) help >&2; exit 1;; # Option not recognized hence print help and exit with error
  esac
done
shift $(( OPTIND-1 )) # Get rid off all options only left arguments starting with $1

# Test arguments
if [ $# -eq 0 ]
then
  help >&2
  err "Missing argument"
fi

# Variables
tmp=$( mktemp -d ) || err "Cannot create temporary directory"
verbose "Created temporary directory ${tmp}"
trap 'rm -rf "$tmp"' EXIT # Run cleanup if script fails before reaching its end

# For loop will go through all arguments by default if "in" is not present
debug "Option argument: ${OPTION_ARGUMENT}"
for script_argument; do
  debug "Script argument: ${script_argument}"
done

# Cleanup
rm -rf "$tmp"
verbose "Deleted temporary directory ${tmp}"