Java exec() does not return expected result of pipes' connected commands

Question

I\'m calling command line programs connected by pipes. All this works on Linux for sure.

My method:

protected String execCommand(String command) thro         


        

Answer 1

The pipe (like redirection, or >) is a function of the shell, and so execing directly from Java won't work. You need to do something like:

/bin/sh -c "your | piped | commands | here"

which executes a shell process with the command line (including pipes) specified after the -c (in quotes).

Note also that you have to consume stdout and stderr concurrently, otherwise your spawned process will block waiting for your process to consume the output (or errors). More info here.