my $string = 'abc!hu(';
print "\Q$string\E\n";    # prints abc\!hu\(
print quotemeta $string;  # prints abc\!hu\(

##</code><code>##

s/\Q$string\E/$replacement/;

# or ..

$qstring = quotemeta $string;
s/$qstring/$replacement/;

##</code><code>##

perldoc perlre
perldoc perlop (the m// part)

##</code><code>##

-- 
Joost       downtime n. The period during which a system
            is error-free and immune from user input.