#!perl -w
use strict;
my $test = 'foo[bar]';
my $test2 = $test;
print $test eq $test2 ? "'$test' is equal to itself\n" : "'$test' is n
+ot equal to itself\n";
print $test =~ /$test2/ ? "'$test' does match itself\n" : "'$test' doe
+s not match itself\n";

__END__

> perl -w tmp.pl
'foo[bar]' is equal to itself
'foo[bar]' does not match itself
[download]

Also see quotemeta and/or \Q..\E.