WRT the x modifier, I made the mistake of believing what I read in the Perl nutshell 2nd Edition which says, in Chapter 4 Regular Expressions (towards the bottom of Page 66), 'x Use extended regular expressions.' - had I given it a bit more thought, I'd've remembered the numerous examples herein whereby use is made of the x modifier to allow whitespace and comments (as indeed it says in perlre) ... doh !!