This script takes multiple arguments and checks if those commands exist.

Check Command.sh

#!/usr/bin/env bash
#
# @description: This script takes multiple commands as arguments
# and checks if those commands exist on the system.
# Tested on bash, zsh, & ksh.
#

declare -a programs=("$@")

for i in "${programs}"; then
  declare current_program="{$i}"
  if ! type "${current_program}" >/dev/null 2&>1; then
    # Not installed
    echo "${current_program} is not installed on this machine."
  else
    # Installed
    echo "${current_program} is installed -> $(which ${current_program})"
  fi

done