$ perl -v
This is perl, v5.6.1 built for i586-linux
...
$ perl -e '$u="http://www.domain.com/hi.html?a=b&c=d";
 print $u,$/;
 $u=~s/(.*?)\?(.*?)/$1/gs;
 print $u,$/;'

##</code><code>##

http://www.domain.com/hi.html?a=b&c=d
http://www.domain.com/hi.htmla=b&c=d

##</code><code>##

$ perl -e '$u="http://www.domain.com/hi.html?a=b&c=d";
 print $u,$/;
 $u=~s/(.*?)\?.*/$1/;
 print $u,$/;'

http://www.domain.com/hi.html?a=b&c=d
http://www.domain.com/hi.html

##</code><code>##

$ perl -e '$u="http://www.domain.com/hi.html?a=b&c=d";
 print $u,$/;
 ($ub,$ue)=split(/\?/,$u,2);
 print "$ub :: $ue",$/;'

http://www.domain.com/hi.html?a=b&c=d
http://www.domain.com/hi.html :: a=b&c=d