in reply to extract ids
perl -lne 'print for /molecule_idref="([^"]+)/g' xmlfile
I've used 'g' modifier to catch ids in a case they occur more than one on a line.
An organised event
A traditional gathering
With family and friends
I don't celebrate the New Year
Adjusting my clocks for the Leap Second
I can't remember
Results (255 votes). Check out past polls.