A stereotypical bash template with simple example patterns. Useful when creating scripts....

template.sh

#!/bin/bash

# Exit immediately for non zero status
set -e
# Check unset variables
set -u
# Print commands
set -x

# Prevent acciedently running as root
if [ "$(id -u)" -eq 0 ]; then
    err "Don't run this script as root"
    exit 1
fi

# Simple way to be notified, 
function bell {
    echo -ne '\a'
}


function spacer {
    printf "\n"
    printf '%*s\n' "${COLUMNS:-$(tput cols)}" '' | tr ' ' -
    printf "\n"
}
function bell {
    echo -ne '\a'
}


function ask  {

    while true; do
        read -p "${1} [Y/n]" yn
        case $yn in
            [Yy]* ) make install; break;;
            [Nn]* ) exit;;
            * ) echo "Please answer yes or no.";;
        esac
    done

}
function err {
    >&2 printf '\n\033[1;31m%s\033[0m\n' "$*"
}


function error_handler {
    MYSELF="$0"
    LASTLINE="$1"
    bell
    err
    err
    err "${MYSELF} failed at line ${LASTLINE}"
    err
    exit 1
}
trap 'error_handler ${LINENO} ${$?}' ERR

function success {
    >&2 printf '\n\033[1;32m%s\033[0m\n' "$*"
}

function warn {
    >&2 printf '\n\033[1;33m%s\033[0m\n' "$*"
}

function info {
    >&2 printf '\n\033[1;39m%s\033[0m\n' "$*"
}


function prompt {
    if [ -z "${QUIET}" ]; then
        bell
        read -rp "$(echo -e '\n\033[1;33mPress [Enter] to continue or [Ctrl + C] to exit...\033[0m')"
        echo
        echo
    fi
}

function with_backoff {
  local max_attempts=${ATTEMPTS-5}
  local timeout=${TIMEOUT-1}
  local attempt=0
  local exitCode=0

  while [[ $attempt < $max_attempts ]]
  do
    "$@"
    exitCode=$?

    if [[ $exitCode == 0 ]]
    then
      break
    fi

    echo "Failure! Retrying in $timeout.." 1>&2
    sleep $timeout
    attempt=$(( attempt + 1 ))
    timeout=$(( timeout * 2 ))
  done

  if [[ $exitCode != 0 ]]
  then
    echo "You've failed me for the last time! ($@)" 1>&2
  fi

  return $exitCode
}

function usage() {
  echo "usage:
        ./template.sh -a <arg_a> -b <arg_b> -z <arg_z>
    e.g.
      ./template.sh -a value_a -b value_b -z 42
    -a name of ah...
    -b name of blah...; default is blah
    -z answer to the universe; default is 42"
  exit 1
}

# commonly used local vars
WD=$(dirname "${0}")
WD=$(cd "${WD}" && pwd)
TIME="$(date '+%Y-%m-%d-%H-%M-%S')"

# Needing a temp dir but still want to clean up? Use this
TMP_DIR=$(mktemp -d -t template-dir)
trap 'rm -rf "${TMP_DIR}"' EXIT

# example to enumerate and put options into local vars and if something else is used, 
# throw out the help message
while getopts a:b:z: arg ; do
  case "${arg}" in
    a) VAR_A_NAME="${OPTARG}";;
    b) VAR_B_NAME="${OPTARG}";;
    z) VAR_Z_NAME="${OPTARG}";;
    *) usage;;
  esac
done

# Conditional on exact value?
if [[ "${VAR_A_NAME}" = "value" ]]; then
    # truthy
else
  # falsy
fi

# Start some process which takes time to warmup, capturing the id and waiting on it for a few seconds
# then when our script exits we also clean up said running process
PROCESS_WAIT=5
echo "Starting process..."
my_process.sh & PF_PID=${!}
# ensure port-forward is actually running
sleep "${PROCESS_WAIT}"; kill -0 "${PF_PID}"
trap 'kill ${PF_PID}' EXIT