Bash / Shell Script: Ensure Minimum Bash Version is Met

version.check.sh

#!/usr/bin/env bash

# = Bash / Shell Script: Ensure Minimum Bash Version is Met
# ? File Name: version.check.sh

# * Echo message, prefixed with timestamp.
# * Optionally, supports color name as argument to alter color of output.
function echoc () {

  # * If no message has been passed, echo an empty line.
  if [ -z "$1" ]; then echo; return; fi

  # * Color Codes
  # = Regular              Bold                      Underline                     High Intensity              BoldHigh Intens                 Background            High Intensity Backgrounds
  # ^ Black='\e[0;30m';    BoldBlack='\e[1;30m';     UnderlineBlack='\e[4;30m';    IntenseBlack='\e[0;90m';    BoldInstenseBlack='\e[1;90m';   On_Black='\e[40m';    On_IntenseBlack='\e[0;100m';
  # ^ Red='\e[0;31m';      BoldRed='\e[1;31m';       UnderlineRed='\e[4;31m';      IntenseRed='\e[0;91m';      BoldInstenseRed='\e[1;91m';     On_Red='\e[41m';      On_IntenseRed='\e[0;101m';
  # ^ Green='\e[0;32m';    BoldGreen='\e[1;32m';     UnderlineGreen='\e[4;32m';    IntenseGreen='\e[0;92m';    BoldInstenseGreen='\e[1;92m';   On_Green='\e[42m';    On_IntenseGreen='\e[0;102m';
  # ^ Yellow='\e[0;33m';   BoldYellow='\e[1;33m';    UnderlineYellow='\e[4;33m';   IntenseYellow='\e[0;93m';   BoldInstenseYellow='\e[1;93m';  On_Yellow='\e[43m';   On_IntenseYellow='\e[0;103m';
  # ^ Blue='\e[0;34m';     BoldBlue='\e[1;34m';      UnderlineBlue='\e[4;34m';     IntenseBlue='\e[0;94m';     BoldInstenseBlue='\e[1;94m';    On_Blue='\e[44m';     On_IntenseBlue='\e[0;104m';
  # ^ Purple='\e[0;35m';   BoldPurple='\e[1;35m';    UnderlinePurple='\e[4;35m';   IntensePurple='\e[0;95m';   BoldInstensePurple='\e[1;95m';  On_Purple='\e[45m';   On_IntensePurple='\e[0;105m';
  # ^ Cyan='\e[0;36m';     BoldCyan='\e[1;36m';      UnderlineCyan='\e[4;36m';     IntenseCyan='\e[0;96m';     BoldInstenseCyan='\e[1;96m';    On_Cyan='\e[46m';     On_IntenseCyan='\e[0;106m';
  # ^ White='\e[0;37m';    BoldWhite='\e[1;37m';     UnderlineWhite='\e[4;37m';    IntenseWhite='\e[0;97m';    BoldInstenseWhite='\e[1;97m';   On_White='\e[47m';    On_IntenseWhite='\e[0;107m';

  # * Color Codes
  local colorReset='\e[0m' # * Color Reset
  local black='\e[1;30m'
  local red='\e[1;31m'
  local green='\e[1;32m'
  local yellow='\e[1;33m'
  local blue='\e[1;34m'
  local purple='\e[1;35m'
  local cyan='\e[1;36m'
  local white='\e[1;37m'

  local activeColor
  local message
  local timestamp

  # * Generate timestamp
  timestamp="$(date +'%Y-%m-%d / T%H:%M:%S%z')"

  # * Message passed.
  message="$1"

  # * If color name is provided, attempt to use that.
  # * Else, default to white.
  activeColor=${!2:-$white}

  # * Echo message with timestamp and optional color code.
  # ? Then you can just echo -e "${Blue}blue ${Red}red ${ResetColor}etc...."
  echo -e "${black}$timestamp: ${activeColor}$message${colorReset}"
}


# * Ensure minimum bash version requirement is met.
# ? Bash version 4 or greater supports associative arrays.
function ensureBashCompatbility () {
  # * Define the minimum support Bash version.
  local minimum_bash_version=6

  echoc 'Ensuring Bash version compatibility.' 'yellow'
  echoc " - Minimum Bash Version Required: $minimum_bash_version"

  # * Exit unless Bash version requirement is met.
  if [[ ! "${BASH_VERSINFO:-0}" -ge "$minimum_bash_version" ]]; then
    echoc
    echoc " ⚠ Fatal Error (Bash Version): This script requires Bash v$minimum_bash_version or greater to execute." red
    echoc "   Bash Version (Current): $BASH_VERSION" red
    echoc

    exit 1
  else
    echoc " ✓ Bash Version: $BASH_VERSION" "green"
    echoc
    echoc
  fi
}

ensureBashCompatbility