pub fn main(world: World) -> Void raises {
    let first: Maybe<String> = std.args.get(1)
    let mode: Maybe<String> = std.env.get("ZERO_CLI_FILE_MODE")
    if first.has && std.mem.eql(first.value, "write") {
        let bytes: Span<u8> = std.mem.span(first.value)
        let written: Maybe<usize> = std.fs.writeBytes(".zero/out/cli-file.txt", bytes)
        if written.has && written.value > 0 && std.fs.exists(".zero/out/cli-file.txt") {
            if mode.has && std.mem.eql(mode.value, "verbose") {
                check world.err.write(mode.value)
                check world.err.write("\n")
            }
            check world.out.write("cli file ok\n")
        }
    } else {
        check world.out.write("pass an argument\n")
    }
}