use warnings;
use strict;
use feature 'say';

while (<DATA>) {
        chomp;
        if (/1([)|\.])(.*)(2\1)/) {
                say $2;
        } else {
                say "BAD LINE:", $_;
        }
}

__DATA__
1) some text 2)
1. some text 2.
1) some text 2.
1. 2.10.10.20 some text 2.
1) 2.10.10.20 2)