$ perl -MData::Dump::Streamer -MYAML -wle 1

$ perl -MData::Dump::Streamer -MYAML -Wle 1
Use of uninitialized value $ENV{"B_UTILS_TRACE"} in addition (+) at /usr/local/lib/perl5/site_perl/5.10.1/x86_32-linux/B/Utils.pm line 72.
Subroutine main::Dump redefined at /usr/local/lib/perl5/5.10.1/lib/Exporter.pm line 67.
 at -e line 0
Name "Exporter::CARP_NOT" used only once: possible typo at /usr/local/lib/perl5/5.10.1/lib/Carp/Heavy.pm line 304.
Name "main::CARP_NOT" used only once: possible typo at /usr/local/lib/perl5/5.10.1/lib/Carp/Heavy.pm line 304.