requires

#!/bin/bash

# Check that passed in requirements are met. Exits with status code 1 if they aren't
# Set DO_NOT_CHECK_REQUIRES=true to avoid checking commands for performance reasons (e.g. for long lists of dependencies that you don't want to check at runtime or if a command calls requires and runs in a tight loop)

[ "$DO_NOT_CHECK_REQUIRES" ] && exit 0

set -ueo pipefail

usage.sh "requires [one or more programs]\ne.g. requires cat tar some_other_program" $@ && exit

exit_code=0

for cmd in "$@"; do
	if [[ -z $(command -v $cmd) ]]; then
		echo "requires: $cmd"
		exit_code=1
	fi
done

exit $exit_code