execute shell command from android

Question

I'm trying to execute this command from the application emulator terminal (you can find it in google play) in this app i write su and press enter, so write:

screenrecord --time-limit 10 /sdcard/MyVideo.mp4

and press again enter and start the recording of the screen using the new function of android kitkat.

so, i try to execute the same code from java using this:

Process su = Runtime.getRuntime().exec("su");
Process execute = Runtime.getRuntime().exec("screenrecord --time-limit 10 /sdcard/MyVideo.mp4");

But don't work because the file is not created. obviously i'm running on a rooted device with android kitkat installed. where is the problem? how can i solve? because from terminal emulator works and in Java not?

score 79 · Accepted Answer · answered Jan 05 '14 at 09:56

79

You should grab the standard input of the su process just launched and write down the command there, otherwise you are running the commands with the current UID.

Try something like this:

try{
    Process su = Runtime.getRuntime().exec("su");
    DataOutputStream outputStream = new DataOutputStream(su.getOutputStream());

    outputStream.writeBytes("screenrecord --time-limit 10 /sdcard/MyVideo.mp4\n");
    outputStream.flush();

    outputStream.writeBytes("exit\n");
    outputStream.flush();
    su.waitFor();
}catch(IOException e){
    throw new Exception(e);
}catch(InterruptedException e){
    throw new Exception(e);
}

answered Jan 05 '14 at 09:56

Carlo Cannas

3,206
19
22

3

Some versions of `su` will take the arguments on the command line, so you could e.g. `exec("su -c screenrecord /sdcard/foo.mp4")`. – fadden Jan 07 '14 at 18:28
7

is it possible to do the recording without root access? – Hendra Anggrian Mar 11 '16 at 07:11
2

big thank you for this snippet, and just to add what I missed in this post is that **there has to be an `\n`** at the end of the command string – rexxar Jun 23 '17 at 14:49
1

it has returned below error. Error running exec(). Command: [su] Working Directory: null Environment: null – Sanjay Bhalani Oct 23 '17 at 13:00
You need to have `su` in your execution path `/system/bin`. @Hendra – Hasibul Hasn Jun 10 '18 at 12:25
1

i run these code and get `su error=13, permission denied`, does it need root privilege? – Bryant Sep 29 '19 at 10:00
it only works with root access ? does any method work without root ? – Ahmad Oct 13 '19 at 11:22

18446744073709551615 · Answer 2 · 2017-10-10T16:45:37.053

A modification of the code by @CarloCannas:

public static void sudo(String...strings) {
    try{
        Process su = Runtime.getRuntime().exec("su");
        DataOutputStream outputStream = new DataOutputStream(su.getOutputStream());

        for (String s : strings) {
            outputStream.writeBytes(s+"\n");
            outputStream.flush();
        }

        outputStream.writeBytes("exit\n");
        outputStream.flush();
        try {
            su.waitFor();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        outputStream.close();
    }catch(IOException e){
        e.printStackTrace();
    }
}

(You are welcome to find a better place for outputStream.close())

Usage example:

private static void suMkdirs(String path) {
    if (!new File(path).isDirectory()) {
        sudo("mkdir -p "+path);
    }
}

Update: To get the result (the output to stdout), use:

public static String sudoForResult(String...strings) {
    String res = "";
    DataOutputStream outputStream = null;
    InputStream response = null;
    try{
        Process su = Runtime.getRuntime().exec("su");
        outputStream = new DataOutputStream(su.getOutputStream());
        response = su.getInputStream();

        for (String s : strings) {
            outputStream.writeBytes(s+"\n");
            outputStream.flush();
        }

        outputStream.writeBytes("exit\n");
        outputStream.flush();
        try {
            su.waitFor();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        res = readFully(response);
    } catch (IOException e){
        e.printStackTrace();
    } finally {
        Closer.closeSilently(outputStream, response);
    }
    return res;
}
public static String readFully(InputStream is) throws IOException {
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    byte[] buffer = new byte[1024];
    int length = 0;
    while ((length = is.read(buffer)) != -1) {
        baos.write(buffer, 0, length);
    }
    return baos.toString("UTF-8");
}

The utility to silently close a number of Closeables (Soсket may be no Closeable) is:

public class Closer {
// closeAll()
public static void closeSilently(Object... xs) {
    // Note: on Android API levels prior to 19 Socket does not implement Closeable
    for (Object x : xs) {
        if (x != null) {
            try {
                Log.d("closing: "+x);
                if (x instanceof Closeable) {
                    ((Closeable)x).close();
                } else if (x instanceof Socket) {
                    ((Socket)x).close();
                } else if (x instanceof DatagramSocket) {
                    ((DatagramSocket)x).close();
                } else {
                    Log.d("cannot close: "+x);
                    throw new RuntimeException("cannot close "+x);
                }
            } catch (Throwable e) {
                Log.x(e);
            }
        }
    }
}
}

score 5 · Answer 3 · edited Nov 04 '16 at 22:35

5

Process p;
StringBuffer output = new StringBuffer();
try {
    p = Runtime.getRuntime().exec(params[0]);
    BufferedReader reader = new BufferedReader(
            new InputStreamReader(p.getInputStream()));
    String line = "";
    while ((line = reader.readLine()) != null) {
        output.append(line + "\n");
        p.waitFor();
    }
} 
catch (IOException e) {
    e.printStackTrace();
} catch (InterruptedException e) {
    e.printStackTrace();
}
String response = output.toString();
return response;

edited Nov 04 '16 at 22:35

Jacob Holloway

887
8
24

answered Jan 11 '15 at 10:19

Balwinder SIngh

1,831
2
24
28

I am not able to launch application using above command executer `am start -n com.qop.tabletApp.activity.ConfigurationAndSetup` – Sagar Sep 02 '20 at 10:01

Bokili Production · Answer 4 · 2022-12-12T21:17:32.693

Late reply, but it will benefit someone. You can use the sh command in the exec() method. Here is my example:

try {
    File workingDirectory = new File(getApplicationContext().getFilesDir().getPath());
    Process shProcess = Runtime.getRuntime().exec("sh", null, workingDirectory);
    try{
        PrintWriter outputExec = new PrintWriter(new OutputStreamWriter(shProcess.getOutputStream()));
        outputExec.println("PATH=$PATH:/data/data/com.bokili.server.nginx/files;export LD_LIBRARY_PATH=/data/data/com.bokili.server.nginx/files;nginx;exit;");
        outputExec.flush();
    } catch(Exception ignored){  }
    shProcess.waitFor();
} catch (IOException ignored) {
} catch (InterruptedException e) {
    try{ Thread.currentThread().interrupt(); }catch(Exception ignored){}
} catch (Exception ignored) { }

What have I done with this? First I call the shell, then I change (set) the necessary environments in it, and finally I start my nginx with it.

This works on unrooted devices too.

Greetings.

score 0 · Answer 5 · answered May 22 '23 at 06:32

0

another solution launch app from android linux shell:

am start -n [your package]/.MainActivity

according Launch an app from Android shell terminal

answered May 22 '23 at 06:32

javaing

33
6

score 0 · Answer 6 · answered Jun 25 '23 at 13:40

@18446744073709551615's answer is great, but there is a much simpler way to use it if the android phone is rooted with newer version of magisk which is to use --command option to run one time command, this makes the code much simpler and less bug prone

import org.apache.commons.lang3.ArrayUtils;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;

public static List<String> sudo(String[] cmd) {
        List<String> res = new ArrayList<String>();
        try {
            String[] fullCmd = ArrayUtils.addAll(new String[]{"su", "--command"}, cmd);
            Process su = Runtime.getRuntime().exec(fullCmd);
            BufferedReader stdInput = new BufferedReader(new
                    InputStreamReader(su.getInputStream()));

            BufferedReader stdError = new BufferedReader(new
                    InputStreamReader(su.getErrorStream()));

            String s;
            while ((s = stdInput.readLine()) != null)
                res.add(s);
            while ((s = stdError.readLine()) != null)
                res.add(s);

        } catch (IOException e) {
            e.printStackTrace();
        }
        return res;
}

execute shell command from android

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