Bash function to see if executable is on $PATH

bash-is-executable-available.sh

#!/bin/bash -e

# Example executables
readonly commands=(python git gitbook cp)

function is_available {
  command -v $1 >/dev/null 2>&1 || { echo >&2 "I require $1 but it's not installed. Aborting."; exit 1; }
}

# Example usage (single)
is_available python;

# Example usage (all elements in array)
for cmd in ${commands[@]}; do is_available "$cmd"; done