Base Template in Shell script for any typical automated instruction on Linux/MacOs

Mother-of-all-bash-scripts.sh

#!/usr/bin/env bash

# A base script to copy & paste typical bash script actions
# You can also use some better like: https://devhints.io/bash

#             DO WHAT THE F*CK YOU WANT TO PUBLIC LICENSE              #
#                     Version 2, December 2004                         #
#                                                                      #
#  Copyright (C) 2004 Sam Hocevar <sam@hocevar.net>                    #
#                                                                      #
#  Everyone is permitted to copy and distribute verbatim or modified   #
#  copies of this license document, and changing it is allowed as long #
#  as the name is changed.                                             #
#                                                                      #
#             DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE              #
#    TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION   #
#                                                                      #
#   0. You just DO WHAT THE FUCK YOU WANT TO.                          #

# Function to check the command executed was ok or cut the execution with a message
function check {
    if [ "$1" -ne 0 ]; then
    echo "\n¯\_(ツ)_/¯ Problem running script. Please check errors. ¯\_(ツ)_/¯\n"
    exit "$1"
  fi
}

# Function to manage optional flags
BUILD_FLAG=true
while [[ "$1" =~ ^- && ! "$1" == "--" ]]; do case $1 in
  -d | --deploy )
    echo "Running with --deploy option (by default)"
    BUILD_FLAG=true
    ;;
  -nd | -n |--no-deploy )
    echo "Running with --no-deploy option"
    BUILD_FLAG=false
    ;;
  -h | --help )
    echo "\nDeploy script usage:"
    echo "--------------------------"
    echo "All the flags are optional, and by default the code its uploaded."
    echo "-d  | --deploy    => Deploy and upload the code to S3 and also upload the IaC stack"
    echo "-nd | --no-deploy => Don't deploy the code to S3, but upload the IaC stack"
    echo "-h  | --help      => Print this usage help\n"
    exit 0
    ;;
  *) echo 'Wrong parameter' >&2
     exit 1
esac; shift; done
if [[ "$1" == '--' ]]; then shift; fi
export BUILD_FLAG

if [ "$BUILD_FLAG" = true ] ; then
  echo "Something happen..."
fi

# 1. Check dependencies
bash --version >/dev/null 2>&1 || { echo >&2 "I require Bash Shell but it's not installed. ¯\_(ツ)_/¯ Aborting."; exit 1; }

# 2. Read a var by keyboard
read -p 'Define a value for $VAR? ' VAR
echo "VAR="$VAR

# 3. Generate an "unique" timestamp enought to file generated in each second
echo "This a timestao for your log> "$(date +'%Y%m%d%H%M%S')

# 4. Test the result of a function:

#false   # Uncomment this to test function error message
true   # Uncomment this to ok behaviour (no message)
check $?

# 5. Ask user if continue with something dangerous:
read -r -p "This script is going to make some dangerous i.e. list current directory. Are you sure? [y/N] " response
if [[ "$response" =~ ^([yY][eE][sS]|[yY])+$ ]]
then
    ls
fi

echo "\n▂▃▅▇█▓▒░ Mission Accomplished ░▒▓█▇▅▃▂\n"

# EOF :)