A generic bash script template.
#!/usr/bin/env bash
# ##################################################
# My Generic BASH script template
#
version="1.0.0" # Sets version variable
#
scriptTemplateVersion="1.5.0" # Version of scriptTemplate.sh that this script is based on
# v1.1.0 - Added 'debug' option
# v1.1.1 - Moved all shared variables to Utils
# - Added $PASS variable when -p is passed
# v1.2.0 - Added 'checkDependencies' function to ensure needed
# Bash packages are installed prior to execution
# v1.3.0 - Can now pass CLI without an option to $args
# v1.4.0 - checkDependencies now checks gems and mac apps via
# Homebrew cask
# v1.5.0 - Now has preferred IFS setting
# - Preset flags now respect true/false
# - Moved 'safeExit' function into template where it should
# have been all along.
#
# HISTORY:
#
# * DATE - v1.0.0 - First Creation
#
# ##################################################
# Provide a variable with the location of this script.
scriptPath="$( 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 "${utilsLocation}"
else
echo "Please find the file util.sh and add a reference to it in this script. Exiting."
exit 1
fi
# trapCleanup Function
# -----------------------------------
# Any actions that should be taken if the script is prematurely
# exited. Always call this function at the top of your script.
# -----------------------------------
function trapCleanup() {
echo ""
# Delete temp files, if any
if is_dir "${tmpDir}"; then
rm -r "${tmpDir}"
fi
die "Exit trapped. In function: '${FUNCNAME[*]}'"
}
# safeExit
# -----------------------------------
# Non destructive exit for when script exits naturally.
# Usage: Add this function at the end of every script.
# -----------------------------------
function safeExit() {
# Delete temp files, if any
if is_dir "${tmpDir}"; then
rm -r "${tmpDir}"
fi
trap - INT TERM EXIT
exit
}
# Set Flags
# -----------------------------------
# Flags which can be overridden by user input.
# Default values are below
# -----------------------------------
quiet=false
printLog=false
verbose=false
force=false
strict=false
debug=false
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'. Mac applications will be installed using
# Homebrew Casks. Ruby and gems via RVM.
# -----------------------------------
homebrewDependencies=()
caskDependencies=()
gemDependencies=()
function mainScript() {
############## Begin Script Here ###################
####################################################
echo -n
####################################################
############### End Script Here ####################
}
############## Begin Options and Usage ###################
# Print usage
usage() {
echo -n "${scriptName} [OPTION]... [FILE]...
This is a script template. Edit this description to print help to users.
${bold}Options:${reset}
-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=true ;;
-l|--log) printLog=true ;;
-q|--quiet) quiet=true ;;
-s|--strict) strict=true;;
-d|--debug) debug=true;;
--force) force=true ;;
--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
# Set IFS to preferred implementation
IFS=$'\n\t'
# 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}; then set -x ; fi
# Exit on empty variable
if ${strict}; 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. Uncomment if needed.
# checkDependencies
# Run your script
mainScript
# Exit cleanlyd
safeExit