What exactly isn't working?

my $str = '<Id>3456</Id>' ;
$str =~ m#(<Id>)(.*)(</Id>)# ;
print "1 - $1\n2 - $2\n3 - $3\n" ;

[ doug 14:49 ~ ]% perl test.pl
1 - <Id>
2 - 3456
3 - </Id>
[download]

BTW, if you're trying to parse XML, take a look at XML::Simple; it does a fine job.

_______________
DamnDirtyApe

Those who know that they are profound strive for clarity. Those who
would like to seem profound to the crowd strive for obscurity.
            --Friedrich Nietzsche