How to capture both STDOUT and STDERR in two different variables using Backticks in Perl

Question

Let\'s say I want to run an external program from my script with backticks and at the same time I want to capture both STDOUT and STDERR but in two different variables. How can

Answer 1

You needn't go all the way to open3, which IIRC is only for when you need to read and write to an external command, and even then there are other methods.

For your problem I suggest using Capture::Tiny, which can capture (or even tee) the STDOUT and STDERR from anything run inside its block. For example, per your question:

#!/usr/bin/env perl

use strict;
use warnings;

use Capture::Tiny qw/capture/;

...

my ($stdout, $stderr) = capture {
  system ( "snmpwalk -v $version -c $community $hostname $oid" );
};

For another example consider this functioning code:

#!/usr/bin/env perl

use strict;
use warnings;

use Capture::Tiny qw/capture/;

my ($stdout, $stderr) = capture {
  system ( "echo 'hello'" );
  system ( "date" );
  warn "Arg1!";
};

print "STDOUT:\n$stdout";
print "STDERR:\n$stderr";

which just gave me:

STDOUT:
hello
Mon Dec 19 23:59:06 CST 2011
STDERR:
Arg1! at ./test.pl line 11.