. is "the current directory" and .. is "the parent directory". File::Spec provides the functions no_upwards, curdir and updir to help deal with them.

#!/usr/bin/env perl
use warnings;
use strict;
use File::Spec::Functions qw/no_upwards curdir updir/;
my $DIR = "/tmp/foo";
opendir my $dh1, $DIR or die $!;
while(my $text = readdir $dh1) {
    next if $text eq updir || $text eq curdir;
    print "1: $text\n";
}
closedir $dh1;
opendir my $dh2, $DIR or die $!;
my @files = no_upwards readdir $dh2;
closedir $dh2;
print "2: $_\n" for @files;

__END__

1: File.txt
2: File.txt
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