You shouldn't need to use PBP for one-liners - that defeats the point. And if you're so worried about it, shouldn't you also be using strict and warnings? In that case, you would see the compilation error

Bareword "no_match_vars" not allowed while "strict subs" in use at ...

promptly fix it with use English qw( -no_match_vars ) and be on your merry way. :)

Update - added the qw (thanks moritz).