There are lots of other options, e.g. System::Command, which let you handle each std stream individually, if you don't have to use qx

There is also Capture::Tiny which will capture your std streams, from manpage:

use Capture::Tiny ':all';
 
my ($stdout, $stderr, $exit) = capture {
  qx/ls -al file-does-not-exist/
};
[download]

p.s. I leave here just for reference a guide to IO redirection in bash - really cool stuff: http://tldp.org/LDP/abs/html/io-redirection.html