Reading the output of a terminal command in java with BufferedReader

Question

Noobie at java just starting, would appreciate any help. So my code is this and for some reason I cant get the output to work..I ve been sitting at this for hours..

package askisi1;

import java.net.*;
import java.util.*;
import java.lang.*;
import java.io.*;


public class Main{

public static void main(String[] args){

    try{

        String command = "ifconfig eth1 | grep -oP '[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}'";
        Process child = Runtime.getRuntime().exec(command);

        System.out.println("So far so good");
        BufferedReader r = new BufferedReader(new InputStreamReader(child.getInputStream()));
        String s;
        while ((s = r.readLine()) != null) {
        System.out.println(s);
        }
        r.close();
        System.out.println("Continue..");
    }
    catch (IOException e) {
        e.printStackTrace();
    }
}



}

This might be a bit duplicate to http://stackoverflow.com/questions/3159913/problem-reading-inputstream-from-java-process-runtime-getruntime-exec-or-pr — Wolfgang Fahl, Oct 21 '12 at 17:47
@WolfgangFahl i researched the question you posted prior to posting my question, but it seemed too complicated working with the thread and cause i haven't been familiar with ProcessBuilder. Thanks for pointing it out though. — Stelios Savva, Oct 22 '12 at 13:25
@jozefg Yes, the command produces the correct output in the terminal — Stelios Savva, Oct 22 '12 at 13:25

Mik378 · Accepted Answer · 2012-10-21T18:17:47.927

Runtime.exec() needs some additional information to execute an Unix Command.

So, assuming my ethernet card is lo0:

String[] command = {
                    "/bin/sh",
                    "-c",
                    "ifconfig lo0 | grep -oP '[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}'"
            }; 
Process child = Runtime.getRuntime().exec(command);
// following here your remaining unchanged code

This prints:

So far so good
127.0.0.1
Continue..

Reading the output of a terminal command in java with BufferedReader

1 Answers1