Add echo command

src/shell.rs

@@ -1,35 +1,40 @@
 use crate::println;
 use crate::print;
 use crate::vga_buffer::{change_color, Color};
+use arrayvec::{ArrayVec, ArrayString};
 
 pub fn evaluate(command: &str) {
     if let Some(stripped) = command.strip_prefix(">>> ") {
         let res = stripped.trim();
         if res != "" {
             println!();
-            let selected = match res {
+            let parts: ArrayVec<&str, 80> = res.split(" ").collect();
+            let selected = match parts[0] {
                 "help" => help,
                 "info" => info,
+                "echo" => echo,
                 _ => default 
             };
-            selected();
+            selected(&parts[..]);
             print!(">>> ");
         }
     }
 }
 
-fn default() {
+fn default(_arguments: &[&str]) {
     println!("Error: unknown command.");
 }
 
-fn help() {
+fn help(_arguments: &[&str]) {
     change_color(Color::LightBlue, Color::Black);
     print!("KarxShell help menu\n\n");
     println!("[help] This message");
+    println!("[info] Info about KarxOS");
+    println!("[echo <arguments>] Echoes whatever arguments you pass in");
     change_color(Color::White, Color::Black);
 }
 
-fn info() {
+fn info(_arguments: &[&str]) {
     print!("KarxOS by ");
     change_color(Color::Blue, Color::Black);
     println!("karx (karx1 on GitHub)");
@@ -40,3 +45,13 @@ fn info() {
     change_color(Color::White, Color::Black);
     println!("If you're having input problems, switch to a US keyboard layout.");
 }
+
+fn echo(arguments: &[&str]) {
+    let mut new: ArrayString<80> = ArrayString::new();
+    for arg in &arguments[1..] {
+        new.push_str(arg);
+        new.push(' ');
+    }
+
+    println!("{}", new);
+}