# uses `whatis` if available to describe a command

function __fish_whatis
	set -l cmd $argv[1]
	set -l fallback
	if set -q argv[2]
		set fallback $argv[2]
	end

	set -l description (whatis $cmd 2>/dev/null | string replace -r '.*? - ' '')[1]
	if not string match -qr -- "$description" "."
		printf '%s\n' $description
		return 0
	else if not string match -q -- "$fallback" ""
		printf '%s\n' $fallback
		return 0
	else
		return 1
	end
end