c:\@Work\Perl\monks>perl -wMstrict -le
"for my $f ('xyz.pl', '.pl', 'abc.x', 'abc') {
   printf qq{%10s matches at position $-[0] \n}, qq{'$f'}
     if $f =~ m{ (?! [.]pl \z) }xms;
   }
"
  'xyz.pl' matches at position 0
     '.pl' matches at position 1
   'abc.x' matches at position 0
     'abc' matches at position 0