$ cat t.pl
#!/usr/bin/perl
use strict;
use warnings;
while (<DATA>) {
    my @f = split /\s+/, $_;
    my $last = pop @f;
    print $last, "\n";
}
__DATA__
the quick red fox
jumped over the lazy
brown dog.  Now is
the time for all
men to come to
the aid of their
party.

$ perl t.pl
fox
lazy
is
all
to
their
party.