Using Java ProcessBuilder to Execute a Piped Command

Question

I\'m trying to use Java\'s ProcessBuilder class to execute a command that has a pipe in it. For example:

ls -l | grep foo

How

Answer 1

This should work:

ProcessBuilder b = new ProcessBuilder("/bin/sh", "-c", "ls -l| grep foo");

To execute a pipeline, you have to invoke a shell, and then run your commands inside that shell.

Answer 2

The simplest way is to invoke the shell with the command line as the parameter. After all, it's the shell which is interpreting "|" to mean "pipe the data between two processes".

Alternatively, you could launch each process separately, and read from the standard output of "ls -l", writing the data to the standard input of "grep" in your example.