$ perl -wle '$msg = qx/ls -K 2>&1/; print "error: $?"; print $msg'
error: 512
ls: invalid option -- K
Try `ls --help' for more information.

##</code><code>##

$ perl -wle '$msg = qx/bash -c ProgramNotExist 2>&1/; print "error: $?"; print $msg'
error: 32512
bash: ProgramNotExist: command not found