First implementation of grrs

After the last chapter on command line arguments, we have our input data, and we can start to write our actual tool. Our main function only contains this line right now:

let args = Cli::from_args();

Let’s start by opening the file we got.

let content = std::fs::read_to_string(&args.path)
    .expect("could not read file");

Now, let’s iterate over the lines and print each one that contains our pattern:

for line in content.lines() {
    if line.contains(&args.pattern) {
        println!("{}", line);

Give it a try: cargo run -- main src/ should work now!