G'day Nansh,

Welcome to the Monastery.

As already pointed out by others, this is a poorly presented question. Without knowing what regex you've used, or what output your current code produces, it's impossible to say, with any certainty, why you're not getting the output you want. Please read "How do I post a question effectively?" before posting again.

As a complete guess, given you need parentheses to capture text that, itself, includes parentheses, you may not have escaped parentheses correctly (see perlre):

$ perl -E 'say +("X(a,b,c)" =~ /X(\([^)]+\))/)[0]'
(a,b,c)
[download]

Also consider stepping through your matching code with Regexp::Debugger.