feat: add more formatting options to time command

src/builtins/time.rs

@@ -1,4 +1,4 @@
-use chrono::{DateTime, Local, TimeZone};
+use chrono::Local;
 
 use crate::error::ShellError;
 
@@ -7,9 +7,20 @@ use super::{Builtin, BuiltinConfig};
 pub struct Time;
 
 impl Builtin for Time {
-    fn execute(&mut self, _: &mut BuiltinConfig, _: Vec<String>) -> Result<(), ShellError> {
+    fn execute(&mut self, _: &mut BuiltinConfig, args: Vec<String>) -> Result<(), ShellError> {
         let time = Local::now();
-        println!("{time}");
+
+        if args.is_empty() {
+            println!("{}", time.format("%T"));
+            return Ok(());
+        }
+
+        let time_string = match args[0].as_str() {
+            "RFC2822" => time.to_rfc2822(),
+            "RFC3339" => time.to_rfc3339(),
+            _ => time.format("%T").to_string(),
+        };
+        println!("{time_string}");
         Ok(())
     }
 }