Hi, Maureen,
To use the very powerful regex search feature, with the PERL syntax, you, absolutely, need an Unicode Notepad++ version >= 6.0
To get your version number, just, hit the F1 key, when a N++ session is opened
As for me, I try to “follow” the different versions, to reply, on that forum, too. So, I use ( one at a time, I’m careful ! ) any portable version, like an old Ansi 5.9.8 version, an Unicode 6.4.5 version, a 6.7.9 version and the last v6.8 version.
You’ll find good documentation, about the new Boost C++ Regex library, v1.55.0 ( similar to the PERL Regular Common Expressions, v1.48.0 ), used by Notepad++, since its 6.0 version, at the TWO addresses below :
http://www.boost.org/doc/libs/1_48_0/libs/regex/doc/html/boost_regex/syntax/perl_syntax.html
http://www.boost.org/doc/libs/1_48_0/libs/regex/doc/html/boost_regex/format/boost_format_syntax.html
The FIRST link explains the syntax, of regular expressions, in the SEARCH part
The SECOND link explains the syntax, of regular expressions, in the REPLACEMENT part
And, if you want, preferably, a general documentation on Notepad++, refer to my post, at the address below :
https://notepad-plus-plus.org/community/topic/40/real-help-wanted/3
Good reading !
Cheers,
guy038