自己写android java 小程序 执行sh命令

package com.example.security;import java.io.IOException;import android.os.Bundle;import android.app.Activity;import android.view.Menu;import android.widget.Button;import android.widget.CompoundButton;import android.widget.Switch;import android.widget.TextView;import java.io.BufferedReader;import java.io.InputStreamReader;public class MainActivity extends Activity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main); Switch switch_contact = (Switch) findViewById(R.id.switch1);  switch_contact.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() { public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) { TextView he= (TextView)findViewById(R.id.textView1); if(isChecked){ he.setText("on"); String s = "/n"; try{ Process p =Runtime.getRuntime().exec("ls /data/"); BufferedReader in = new BufferedReader(                           new InputStreamReader(p.getInputStream()));       String line = null;       while ((line = in.readLine()) != null) {           s += line + "/n";                  }       he.setText(s);  } catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}   }else{ he.setText("off"); } }  });}    @Overridepublic boolean onCreateOptionsMenu(Menu menu) {// Inflate the menu; this adds items to the action bar if it is present.getMenuInflater().inflate(R.menu.main, menu);return true;}}

ls /data/ 是非法的

但是可以cat /proc/verions