feat: add open command

src/builtins/open.rs

@@ -1,3 +1,5 @@
+use std::{fs::File, io::stdout};
+
 use crate::error::ShellError;
 
 use super::{Builtin, BuiltinConfig};
@@ -5,7 +7,18 @@ use super::{Builtin, BuiltinConfig};
 pub struct Open;
 
 impl Builtin for Open {
-    fn execute(&mut self, _: &mut BuiltinConfig, _: Vec<String>) -> Result<(), ShellError> {
+    fn execute(&mut self, _: &mut BuiltinConfig, args: Vec<String>) -> Result<(), ShellError> {
+        let path = match args.get(0) {
+            Some(p) => p,
+            None => return Err(ShellError::MalformedArgs("No file specified".to_string())),
+        };
+        let mut file = match File::open(path) {
+            Ok(f) => f,
+            Err(e) => return Err(ShellError::ExecuteFailure(e.to_string())),
+        };
+        if let Err(e) = std::io::copy(&mut file, &mut stdout()) {
+            return Err(ShellError::ExecuteFailure(e.to_string()));
+        }
         Ok(())
     }
 }