function findstr
    if test (count $argv) -lt 1
        echo "Usage: findstr <search-string>"
        return 1
    end
    if not command -q find
        echo "findstr: 'find' is not installed."
        return 1
    end
    if not command -q grep
        echo "findstr: 'grep' is not installed."
        return 1
    end

    find . -type f -exec grep -Hn "$argv[1]" {} \;
end