bobhussey has asked for the wisdom of the Perl Monks concerning the following question:

I want to start a process in the background, redirect it's output to a file, and get the pid of the process i just started. Is there a way to do all of this (I can figure out how to do any two of the 3 but not all three). Thanks, Bob
  • Comment on Doing a system command and getting the pid

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Re: Doing a system command and getting the pid
by borisz (Canon) on Jan 21, 2005 at 00:35 UTC
    untested: 
    my $pid = open( my $fh, 'your_command 1>/tmp/xxx 2>&1 |' );

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    Boris
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Re: Doing a system command and getting the pid
by Tanktalus (Canon) on Jan 21, 2005 at 00:25 UTC

    It'd be nice if you gave us what you had tried. It really does help. Anyway ... Off the top of my head, untested: 

    FORK:
{
 if (my $child = fork())
 {
   print "Child process ID: $child\n";
 }
 elsif (not defined $child)
 {
   # failed to fork.
   next FORK;
 }
 else
 {
   # child.
   open(STDOUT, '>somefile);
   close(STDIN); # just good practice for background procs
   exec($program, @program_args);
 }
}

    [download]
    Update: Fixed the off-by-everything error as noted by Eimi Metamorphoumai - thanks!

[reply]
[d/l]
      I think you've got your if backwards. fork returns zero to the child, and gives the parent the child's pid, so you want to do your exec in the case that $child is 0 (but defined).
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Re: Doing a system command and getting the pid
by eyepopslikeamosquito (Archbishop) on Jan 21, 2005 at 04:44 UTC
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