$command = "curl -D- http://www.perlmonks.org";  # mixes stderr and stdout

# stdout only, no stderr noise 
$stdout_only  = `$command  2>/dev/null`;

# stderr only, no stdout noise         
$stderr_only = `$command  2>&1 1>/dev/null`;

# both mixed up (usually not a good idea!)
# Aliens suggestion to use open3 is better in this case.
$brundlefly  = `$command  2>&1`;