$ cat main.pl 
#!/usr/bin/perl
use warnings;
use strict;
open (IN, '-|', 'perl PrintStdoutStdErr.pl') or die "$!";
while (<IN>) {
	chomp;
    print "\"$_\"\n";
}
$ perl main.pl 1>out 2>err
$ cat out
"this went to STDOUT"
$ cat err
this went to STDERR