Regex problem

[Tu Nguyen]

Hi all,

Can somebody show me how to use regular expression to subtitute a string
with speacial character such as [* , ?]  in it ?

for example

$string = 'test ? test';
$input = 'Start test ? test End';
$change = 'Change';

$input =~ s/$string/$change/g;

After change, I expect $input = 'Start Change End'  but I never got it.

Thanks alot for any help.

Nguyen