Event.control

Description

Is Control key held down? (Read Only)

Returns true if any Control key is held down.

// Detects if the control key was pressed
function OnGUI() {
    var e : Event = Event.current;
    if (e.control) {
        Debug.Log("Control was pressed.");
    }
}

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour {
    void OnGUI() {
        Event e = Event.current;
        if (e.control)
            Debug.Log("Control was pressed.");
        
    }
}