Java: is there a way to run a system command and print the output during execution?

Question

I have a python script and it takes a long time to finish. I would like to run it from Java, but also output the script\'s output while it is executing, so that I can tell i

Answer 1

i managed to get it working like this (Note it requires java7):

package test;
import java.lang.ProcessBuilder.Redirect;

public class Test {

    public static void main(String... args) throws Exception {
        ProcessBuilder pb = new ProcessBuilder("python","/home/foobar/Programming/test/src/test/test.py");
        pb.redirectOutput(Redirect.INHERIT);
        Process p = pb.start();
        p.waitFor();
    }

}

python (note i flush on python to make it work using sys.stdout.flush())

import time,sys
c =0
while c<=50:
    time.sleep(1)
    print("----")
    c = c +1
    sys.stdout.flush()

Note if you don't want to flush in a loop you can use this:

ProcessBuilder pb = new ProcessBuilder("python","-u","/home/foobar/Programming/NetBeansProjects/test/src/test/test.py");

Redirect.INHERIT

Indicates that subprocess I/O source or destination will be the same as those of the current process. This is the normal behavior of most operating system command interpreters (shells).