text markup underlining

[Jean-marc LEGRAND]

XP + lily 2.10

Hi list !

Coming from the french list where we are several to seeking a simple way of 
underlining text :

Is there a simple way to underline text in markups (and everywhere else, such 
as headers) ?

I've seen in the list something like \\underline, but it doesn't work at all. 
I'd be very surprised
to learn that something as simple as \bold or \italic doesn't exist for 
underlining...

Best regards !

JMarc