运行linux命令 （转载）
Android运行底层linux外部命令的实现
android的底层实际是Linux内核，当然在shell环境下可以运行linux命令，尤其是经过root处理的android系统，基本上可以通过调用linux命令完全控制手机，下面的RootCmd.java代码就是实现运行linux外部命令。

package my.android.code;

import android.os.Environment;
import dalvik.annotation.Signature;
import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileReader;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Vector;

public final class RootCmd
{
  //执行linux命令并且输出结果
  protected static Vector execRootCmd(String paramString)
  {
    Vector localVector = new Vector();
    try
    {
      Process localProcess = Runtime.getRuntime().exec("su ");//经过Root处理的android系统即有su命令
      OutputStream localOutputStream = localProcess.getOutputStream();
      DataOutputStream localDataOutputStream = new DataOutputStream(localOutputStream);
      InputStream localInputStream = localProcess.getInputStream();
      DataInputStream localDataInputStream = new DataInputStream(localInputStream);
      String str1 = String.valueOf(paramString);
      String str2 = str1 + "\n";
      localDataOutputStream.writeBytes(str2);
      localDataOutputStream.flush();
      String str3 = localDataInputStream.readLine();
      localVector.add(str3);
      localDataOutputStream.writeBytes("exit\n");
      localDataOutputStream.flush();
      localProcess.waitFor();
      return localVector;
    }
    catch (Exception localException)
    {
      localException.printStackTrace();
    }
  }

   //执行linux命令但不关注结果输出
  protected static int execRootCmdSilent(String paramString)
  {
    try
    {
      Process localProcess = Runtime.getRuntime().exec("su");
      Object localObject = localProcess.getOutputStream();
      DataOutputStream localDataOutputStream = new DataOutputStream((OutputStream)localObject);
      String str = String.valueOf(paramString);
      localObject = str + "\n";
      localDataOutputStream.writeBytes((String)localObject);
      localDataOutputStream.flush();
      localDataOutputStream.writeBytes("exit\n");
      localDataOutputStream.flush();
      localProcess.waitFor();
      localObject = localProcess.exitValue();
      return localObject;
    }
    catch (Exception localException)
    {
      localException.printStackTrace();
    }
  }

//判断机器Android是否已经root，即是否获取root权限
  protected static boolean haveRoot()
  {

    int i = execRootCmdSilent("echo test"); //通过执行测试命令来检测
    if (i != -1)  return true;
    retrun false;
  }

}