Shell

main.rs

use std::io::stdin;
use std::io::stdout;
use std::io::Write;
use std::process::Command;
use std::process::Stdio;
use std::process::Child;
use std::env;
use std::path::Path;

fn main(){
    loop {
        print!("> ");
        stdout().flush();

        let mut input = String::new();

        stdin().read_line(&mut input).unwrap();

        let mut commands = input.trim().split(" | ").peekable();
        let mut previous_command = None;

        while let Some(command) = commands.next(){
            let mut parts = input.trim().split_whitespace();
            let command = parts.next().unwrap();
            let args = parts;

            match command {
                "cd" => {
                    let new_dir = args.peekable().peek().map_or("/", |x| *x);
                    let root = Path::new(new_dir);

                    if let Err(e) = env::set_current_dir(&root) {
                        eprintln!("{}", e)
                    }
                    previous_command = None;
                },
                "exit" => return,

                command => {
                    let stdin = previous_command
                        .map_or(
                            Stdio::inherit(),
                            |output: Child| Stdio::from(output.stdout.unwrap())
                        );
                    let stdout = if commands.peek().is_some(){
                        Stdio::piped()
                    } else {
                        Stdio::inherit()
                    };
                    let output = Command::new(command)
                        .args(args)
                        .stdin(stdin)
                        .stdout(stdout)
                        .spawn();

                    match output {
                        Ok(mut output) => {  previous_command = Some(output); },
                        Err(e) => {
                            previous_command = None;
                            eprintln!("{}", e);
                        },
                    };
                }
            }
        }
        if let Some(mut final_command) = previous_command {
            final_command.wait();
        }
    }
}