pb.java

import java.io.*;

public class Pb {
    public static void main(String[] args){
        try{
            ProcessBuilder pb = new ProcessBuilder("ls -lrt");
            Process p = pb.start();
            BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream()));
            File file = new File("output.txt");
            BufferedWriter output = new BufferedWriter(new FileWriter(file));
            String line = br.readLine();
            while(line != null){
                output.write(line + "\n");
                line = br.readLine();
            }
            output.close();
            br.close();
        }catch(Exception e){
            e.printStackTrace();
        }
        System.out.println("File written!");
    }
}