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Groups > comp.lang.java.programmer > #31815

Re: Getting results of command execution

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On 6/17/2015 4:56 PM, FredK wrote:
> I want to execute a set of commands and get the results. So I start with,
> on Unix;
>    process P = Runtime.getRuntime().exec("commandA; commandB");
>
> or on Windows
>    process P = Runtime.getRuntime().exec("commandA & commandB");
>
> How do I get the results of the output AND error output in the order they are created?
>
> If I use this type of coding:
> [...]
> I get all of the stdout, followed by all of the stderr. But suppose commandA writes some output, then some errors, then more outputs, etc. I want to retrieve them in that order.

     You could try using a ProcessBuilder to set up your Process, and
use its redirectErrorStream() method to merge stdout and stderr before
calling start().  But even then, you'll be at the mercy of whatever
buffering takes place in the external process itself: If that process
holds on to stdout data until it's got a bufferload, but emits stderr
data right away (this is the default behavior for many C programs),
the mingled data will be temporally scrambled no matter what you do
on the receiving side.

-- 
esosman@comcast-dot-net.invalid
"Don't be afraid of work. Make work afraid of you." -- TLM

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Thread

Getting results of command execution FredK <fred.l.kleinschmidt@gmail.com> - 2015-06-17 13:56 -0700
  Re: Getting results of command execution Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-06-17 17:14 -0400
    Re: Getting results of command execution FredK <fred.l.kleinschmidt@gmail.com> - 2015-06-17 14:57 -0700
      Re: Getting results of command execution Martin Gregorie <martin@address-in-sig.invalid> - 2015-06-17 23:07 +0000
      Re: Getting results of command execution Jeff Higgins <jeff@invalid.invalid> - 2015-06-17 21:26 -0400
        Re: Getting results of command execution FredK <fred.l.kleinschmidt@gmail.com> - 2015-06-18 07:18 -0700
        Re: Getting results of command execution FredK <fred.l.kleinschmidt@gmail.com> - 2015-06-18 07:30 -0700
          Re: Getting results of command execution Jeff Higgins <jeff@invalid.invalid> - 2015-06-18 17:37 -0400
            Re: Getting results of command execution FredK <fred.l.kleinschmidt@gmail.com> - 2015-06-19 07:50 -0700
              Re: Getting results of command execution Jeff Higgins <jeff@invalid.invalid> - 2015-06-19 21:33 -0400
                Re: Getting results of command execution Jeff Higgins <jeff@invalid.invalid> - 2015-06-19 21:56 -0400
                Re: Getting results of command execution Jeff Higgins <jeff@invalid.invalid> - 2015-06-19 23:02 -0400
                Re: Getting results of command execution Jeff Higgins <jeff@invalid.invalid> - 2015-06-20 11:11 -0400
                Re: Getting results of command execution Jeff Higgins <jeff@invalid.invalid> - 2015-06-20 12:14 -0400
                Re: Getting results of command execution Jeff Higgins <jeff@invalid.invalid> - 2015-06-20 20:58 -0400
          Re: Getting results of command execution Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-06-19 11:01 -0400
      Re: Getting results of command execution Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-06-18 08:38 -0400
  Re: Getting results of command execution Jeff Higgins <jeff@invalid.invalid> - 2015-07-03 23:41 -0400

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