qw/STRING/ Returns a list of the words extracted out of STRING, using embedded whitespace as the word delimiters. It is exactly equivalent to split(' ', q/STRING/); This equivalency means that if used in scalar context, you'll get split's (unfortunate) scalar context behavior, complete with mysterious warnings. Some frequently seen examples: use POSIX qw( setlocale localeconv ) @EXPORT = qw( foo bar baz ); A common mistake is to try to separate the words with comma or to put comments into a multi-line perlman:perlop-string. For this reason the -w switch produce warnings if the STRING contains the ``,'' or the ``#'' character.