Feat: Implement 'cls' command using native OS calls

Author: HossamSaberr

src/main/java/com/mycmd/App.java

@@ -106,6 +106,7 @@ private static void registerCommands(Map<String, Command> commands) {
         commands.put("unalias", new UnaliasCommand());
         commands.put("rename", new RenameCommand());
         commands.put("set", new SetCommand());
+        commands.put("cls", new ClsCommand());
           }
 }
 

src/main/java/com/mycmd/commands/ClsCommand.java

@@ -3,22 +3,35 @@
 import com.mycmd.Command;
 import com.mycmd.ShellContext;
 
+import java.io.IOException;
+
 /**
- * Clears the console screen by printing multiple blank lines.
- * 
- * This command simulates clearing the terminal screen by outputting 50 blank
- * lines, pushing previous content out of view. This is a simple cross-platform
- * approach that doesn't rely on terminal-specific control sequences.
- * 
+ * Clears the console screen using the native OS command.
+ *
+ * This command clears the terminal screen by executing the 'cls' command
+ * on Windows or the 'clear' command on Unix-like systems (macOS, Linux).
+ * This provides a true clear-screen functionality.
+ *
  * Usage: cls
- * 
+ *
  * Note: This command does not accept any arguments.
  */
 public class ClsCommand implements Command {
+
     @Override
     public void execute(String[] args, ShellContext context) {
-        for (int i = 0; i < 50; i++) {
-            System.out.println();
+        try {
+            String os = System.getProperty("os.name").toLowerCase();
+            if (os.contains("win")) { // For Windows Users
+                new ProcessBuilder("cmd", "/c", "cls").inheritIO().start().waitFor();
+            } else { // For other Operation Systems
+                new ProcessBuilder("clear").inheritIO().start().waitFor();
+            }
+        } catch (InterruptedException e) { // Restore the interrupted status
+            Thread.currentThread().interrupt();
+            System.out.println("Error while clearing the screen: " + e.getMessage());
+        } catch (IOException e) {
+            System.out.println("Error while clearing the screen: " + e.getMessage());
         }
     }
-}
+}