Executing linux commands from Java

package sunels;

import java.io.*;

public class LinuxCommandExecutor {
public static void main (String args[]) {
try {
ProcessBuilder pb = new ProcessBuilder ("/bin/grep", "phoneNumber", "/space/subscribersDBdump.txt");

Process proc = pb.start ();

BufferedInputStream in = new BufferedInputStream (proc.getInputStream ());
FileOutputStream fout = new FileOutputStream ("/space/phoneNumbersOnly.txt");

byte[] buffer = new byte[2048];

while (true) {
int nRead = in.read (buffer);

if (nRead == -1)
break;

fout.write (buffer, 0, nRead);
System.out.print (".");
}

fout.close ();
proc.waitFor ();

}
catch (Exception e) {
e.printStackTrace ();
}
}
}