The character controllers step offset in meters.

	// Set the controller step offset to 2.0
	var controller : CharacterController;
	controller = GetComponent(CharacterController);
	controller.stepOffset = 2.0;

using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour {
    public CharacterController controller;
    void Example() {
        controller = GetComponent<CharacterController>();
        controller.stepOffset = 2.0F;
    }
}

import UnityEngine
import System.Collections

public class Example(MonoBehaviour):

	public controller as CharacterController

	def Example() as void:
		controller = GetComponent[of CharacterController]()
		controller.stepOffset = 2.0F