I get differing results - the following prints nothing on Panther, Perl 5.8.1:

  #! /usr/bin/perl -w
  use strict;

  print "File exists.\n" if -e ' ';
  print "File exists.\n" if -e ' . . ';
  print "File exists.\n" if -e ' .. ';
  print "File exists.\n" if -e '           ';
  print "File exists.\n" if -e '.          ';
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Update: Clarified code.