GetComponent(TextMesh).alignment = TextAlignment.Left;

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
void Awake() {
GetComponent<TextMesh>().alignment = TextAlignment.Left;
}
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

def Awake():
GetComponent[of TextMesh]().alignment = TextAlignment.Left