bester:~> perl -Mstrict -Mwarnings -le 'print "defined!" if defined( (split /\//, "2|3|||||")[4]);'
bester:~>

##</code><code>##

bester:~> perl -Mstrict -Mwarnings -le 'print "defined!" if defined( (map { defined($_) ? $_ : ""; } (split /\//, "2|3|||||") )[4]);'
bester:~>