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javapipeprocessbuilder

Building a process pipe with ProcessBuilder in Java 7

I've been trying to figure out how to pipe a few processes in Java using the new ProcessBuilder. I can't find a suitable example of what I want to do and when I try to do it myself the process just hangs. I would appreciate a very simple example of some code that runs the equivalent of cat test.txt | wc, but not through a shell.

--Update--

OK, just to clarify. I know there are ways to simulate a pipe by reading and writing streams. I'm wondering if that's done in some automatic way by the redirectInput and redirectOutput methods introduced in Java 7.

Solution

  • You don't need a pipe in this case.

    "grep bla test.txt"

    however assuming you need a pipe, you need to use a shell like bash

    "/bin/bash", "-c", "grep foo text.txt | grep bar"