feat: add very basic ash shell clone

this supports no scripting at all!

shell/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "shell"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+boxutils = { path = "../utils" }

shell/src/ash.rs

@@ -0,0 +1,56 @@
+use boxutils::commands::Command;
+use std::env;
+use std::process::Command as stdCommand;
+use std::io::{self, Write, ErrorKind};
+use std::path::Path;
+use std::fmt;
+
+pub struct Ash;
+
+impl Command for Ash {
+    fn execute(&self) {
+        loop {
+            let path = env::current_dir();
+            print!(
+                "{} $ ", // TODO: display "#" if root
+                path.expect("unknown").display()
+            );
+            let _ = io::stdout().flush();
+            let mut input = String::new();
+            io::stdin().read_line(&mut input).unwrap();
+            let mut full_cmd = input.trim().split_whitespace();
+            let command = full_cmd.next().unwrap();
+            let mut arguments = full_cmd;
+            match command {
+                "exit" => return,
+                "cd" => {
+                    let new_path = arguments.next();
+                    let new_path = Path::new(new_path.unwrap());
+                    let _ = env::set_current_dir(&new_path).is_ok();
+                },
+                command => {
+                    let out = stdCommand::new(command)
+                        .args(arguments)
+                        .spawn();
+
+                    match out {
+                        Ok(mut out) => {
+                           let _ = out.wait();
+                        },
+                        Err(err) => match err.kind() {
+                            ErrorKind::NotFound => {
+                                eprintln!("ash: {}: not found", command);
+                            }
+                            ErrorKind::PermissionDenied => {
+                                eprintln!("ash: {}: permission denied", command);
+                            }
+                            _ => {
+                                eprintln!("ash: uncaught error: {}", err);
+                            }
+                        }
+                    }
+                },
+            }
+        }
+    }
+}

shell/src/lib.rs

@@ -0,0 +1 @@
+pub mod ash;