undef $/;
$current = <DATA>;
$start   = '<!---CURCON-->';
$end     = '<!---END CURCON-->';

my ($match) = $current =~ m/$start(.*)$end/s;
print $match;

__DATA__
stuff i don't want
<!---CURCON-->
stuff i do want
<!---END CURCON-->
more stuff i don't want

##</code><code>##

my ($match) = $current =~ m/$start(.*)$end/s; # note the parens around $match

##</code><code>##

$match =~ tr/\n//d;
# or
$match =~ s/\n//g;