C:\test>p1
$_ = '   the quick    brown fox   ';;

print join'|', split;;   ## default split no args (leading null field omitted)
the|quick|brown|fox

print join'|', split /\s+/;; ## \s+ includes leading null field
|the|quick|brown|fox

print join'|', split / /;; ## same as split /\s/
|||the|quick||||brown|fox

print join'|', split ' ';; ## Same as no arg split
the|quick|brown|fox