$ perl -Mstrict -w 
my $ext = ".var";
my @filenames = qw( otto.var evar.txt nix.var.here );


print "einfacher Regex\n";

for my $file ( @filenames ) {
  print $file, "\n" if $file =~ m/$ext/;
}

print "entwerte enthaltene Sonderzeichen wie .\n";
for my $file ( @filenames ) {
  print $file, "\n" if $file =~ m/\Q$ext\E/;
}

print "entwerte Sonderzeichen und verankere Regex.\n";
for my $file ( @filenames ) {
  print $file, "\n" if $file =~ m/\Q$ext\E$/;
}

^D