Boilerplate Shell Script Template | Nathaniel Landau

#!/usr/bin/env bash

# ##################################################
# My Generic BASH script template
#
version="1.0.0"               # Sets version variable
#
scriptTemplateVersion="1.3.0" # Version of scriptTemplate.sh that this script is based on
#                               v.1.1.0 - Added 'debug' option
#                               v.1.1.1 - Moved all shared variables to Utils
#                                       - Added $PASS variable when -p is passed
#                               v.1.2.0 - Added 'checkDependencies' function to ensure needed
#                                         Bash packages are installed prior to execution
#                               v.1.3.0 - Can now pass CLI without an option to $args
#
# HISTORY:
#
# * DATE - v1.0.0  - First Creation
#
# ##################################################

# Provide a variable with the location of this script.
scriptPath="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"

# Source Scripting Utilities
# -----------------------------------
# These shared utilities provide many functions which are needed to provide
# the functionality in this boilerplate. This script will fail if they can
# not be found.
# -----------------------------------

utilsLocation="${scriptPath}/lib/utils.sh" # Update this path to find the utilities.

if [ -f "${utilsLocation}" ]; then
  source "${utilsLocation}"
else
  echo "Please find the file util.sh and add a reference to it in this script. Exiting."
  exit 1
fi

# trapCleanup Function
# -----------------------------------
# Any actions that should be taken if the script is prematurely
# exited.  Always call this function at the top of your script.
# -----------------------------------
function trapCleanup() {
  echo ""
  if is_dir "${tmpDir}"; then
    rm -r "${tmpDir}"
  fi
  die "Exit trapped."  # Edit this if you like.
}

# Set Flags
# -----------------------------------
# Flags which can be overridden by user input.
# Default values are below
# -----------------------------------
quiet=0
printLog=0
verbose=0
force=0
strict=0
debug=0
args=()

# Set Temp Directory
# -----------------------------------
# Create temp directory with three random numbers and the process ID
# in the name.  This directory is removed automatically at exit.
# -----------------------------------
tmpDir="/tmp/${scriptName}.$RANDOM.$RANDOM.$RANDOM.$$"
(umask 077 && mkdir "${tmpDir}") || {
  die "Could not create temporary directory! Exiting."
}

# Logging
# -----------------------------------
# Log is only used when the '-l' flag is set.
#
# To never save a logfile change variable to '/dev/null'
# Save to Desktop use: $HOME/Desktop/${scriptBasename}.log
# Save to standard user log location use: $HOME/Library/Logs/${scriptBasename}.log
# -----------------------------------
logFile="$HOME/Library/Logs/${scriptBasename}.log"

# Check for Dependencies
# -----------------------------------
# Arrays containing package dependencies needed to execute this script.
# The script will fail if dependencies are not installed.  For Mac users,
# most dependencies can be installed automatically using the package
# manager 'Homebrew'.
# -----------------------------------
homebrewDependencies=()

function mainScript() {
############## Begin Script Here ###################
####################################################

echo -n

####################################################
############### End Script Here ####################
}

############## Begin Options and Usage ###################


# Print usage
usage() {
  echo -n "${scriptName} [OPTION]... [FILE]...

This is my script template.

 Options:
  -u, --username    Username for script
  -p, --password    User password
  --force           Skip all user interaction.  Implied 'Yes' to all actions.
  -q, --quiet       Quiet (no output)
  -l, --log         Print log to file
  -s, --strict      Exit script with null variables.  i.e 'set -o nounset'
  -v, --verbose     Output more information. (Items echoed to 'verbose')
  -d, --debug       Runs script in BASH debug mode (set -x)
  -h, --help        Display this help and exit
      --version     Output version information and exit
"
}

# Iterate over options breaking -ab into -a -b when needed and --foo=bar into
# --foo bar
optstring=h
unset options
while (($#)); do
  case $1 in
    # If option is of type -ab
    -[!-]?*)
      # Loop over each character starting with the second
      for ((i=1; i < ${#1}; i++)); do
        c=${1:i:1}

        # Add current char to options
        options+=("-$c")

        # If option takes a required argument, and it's not the last char make
        # the rest of the string its argument
        if [[ $optstring = *"$c:"* && ${1:i+1} ]]; then
          options+=("${1:i+1}")
          break
        fi
      done
      ;;

    # If option is of type --foo=bar
    --?*=*) options+=("${1%%=*}" "${1#*=}") ;;
    # add --endopts for --
    --) options+=(--endopts) ;;
    # Otherwise, nothing special
    *) options+=("$1") ;;
  esac
  shift
done
set -- "${options[@]}"
unset options

# Print help if no arguments were passed.
# Uncomment to force arguments when invoking the script
# [[ $# -eq 0 ]] && set -- "--help"

# Read the options and set stuff
while [[ $1 = -?* ]]; do
  case $1 in
    -h|--help) usage >&2; safeExit ;;
    --version) echo "$(basename $0) ${version}"; safeExit ;;
    -u|--username) shift; username=${1} ;;
    -p|--password) shift; echo "Enter Pass: "; stty -echo; read PASS; stty echo;
      echo ;;
    -v|--verbose) verbose=1 ;;
    -l|--log) printLog=1 ;;
    -q|--quiet) quiet=1 ;;
    -s|--strict) strict=1;;
    -d|--debug) debug=1;;
    --force) force=1 ;;
    --endopts) shift; break ;;
    *) die "invalid option: '$1'." ;;
  esac
  shift
done

# Store the remaining part as arguments.
args+=("$@")

############## End Options and Usage ###################




# ############# ############# #############
# ##       TIME TO RUN THE SCRIPT        ##
# ##                                     ##
# ## You shouldn't need to edit anything ##
# ## beneath this line                   ##
# ##                                     ##
# ############# ############# #############

# Trap bad exits with your cleanup function
trap trapCleanup EXIT INT TERM

# Exit on error. Append '||true' when you run the script if you expect an error.
set -o errexit

# Run in debug mode, if set
if [ "${debug}" == "1" ]; then
  set -x
fi

# Exit on empty variable
if [ "${strict}" == "1" ]; then
  set -o nounset
fi

# Bash will remember & return the highest exitcode in a chain of pipes.
# This way you can catch the error in case mysqldump fails in `mysqldump |gzip`, for example.
set -o pipefail

# Invoke the checkDependenices function to test for Bash packages
checkDependencies

# Run your script
mainScript

safeExit # Exit cleanly