No problem ! So :

1) :

Casey, the first part, of the regex, (?-s), is NOT a group, at all ! It’s an in-line pattern modifier. Our N++ regex engine can understand four modifiers :

• The (?-s) modifier means that the dot ( . ) meta-character matches standard characters, ONLY, ( except for the \f character ), even if you previously checked the . matches newline option. The opposite syntax, (?s), would force the regex engine to consider that the dot matches ANY character ( standard and EOL charcraters ), even if you did not check, previously, the .matches newline option.

• The (?-i) modifier forces the regex engine to search, in a sensitive way, even you did not check, previously, the Match case option. The opposite syntax (?i) would do a search, rergardless to case of letters, even if you, previously, checked the Match case option.

Two other modifiers, less used, are, also, available :

• The (?m) modifier, which means that the ^ and $ assertions represent, respectively, the beginning and end of any line ( default N++ behaviour ). The opposite syntax (?-m) means that the ^ and $ assertions represent, ONLY, the very beginning and the very end of the file

• The (?-x) modifier, which means that any space character, in the regex, is significant ( default N++ behaviour ). The opposite syntax (?x) means that you may separate the different parts of a complex regex with some space character, which are ignored by the regex engine. Note the the two syntaxes [ ], with a space between the two square brackets or \ , with a space, after the anti-slash character, stands for an true space character !

• Note that you may group these modifiers, as, for instance, (?s-i) or (?xi-s) and that a modifier takes effect, till the opposite form is found, further on, in the regex or, of course, till the end of the regex

2) :

• Outside a character class ( [....] ), the escape sequence \R matches ANY Unicode New line sequence. The exact definition of the escape sequence \R is (?>\r\n|[\n\x0b\f\r\x85\x{2028}\x{2029}]).

• Just notice the atomic group contruction, which means that, for instance, if the \R form would match the two End-of-Line characters \r\n, the regex engine will never try to backtrack, for matching the possible remainder of the overall regex, located after an \R !

• But, most of the time, we may, simply, consider that the \R syntax matches ANY kind of EOL character :

  • The sequence \r\n ( case of a Windows End of Line )

  • The \n character ( case of a Unix End of Line )

  • The \r character ( case of a Machintosh End of Line )

Therefore, the regex (?-s)(^.*\R)\1+ tries to find :

• From beginning of line, ANY range of standard characters, even empty, followed by the current EOL character(s)

• This complete current line is stored as group 1, due to the couple of parentheses, after the modifier

• The regex engine, then, searches for any additional line(s), identical to the previous one ( The + quantifier is equivalent to {1,} )

• In replacement, the block of identical lines ( the first and the additional ones ) is replaced by ONE occurrence, only, of that line ( \1 ) !

To go further on, refer, firstly, to the Notepad++ wiki article, dealing with regular expressions, :

http://docs.notepad-plus-plus.org/index.php/Regular_Expressions

In addition, 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

You may, also, look for valuable informations, on the sites, below :

http://www.regular-expressions.info

http://www.rexegg.com

http://perldoc.perl.org/perlre.html

Best Regards,

guy038

Quite easy ! Once you get your results, in the Find Result panel :

• RIGHT-click on the green line, with the absolute path of your file, and the number of hits

• Select the option Copy

• Open a new tab ( Ctrl + N )

• Click on this new file to get the focus

• Paste the clipboard contents ( Ctrl +V )

• Move back to the very beginning of this new file

• Open the Replace dialog ( Ctrl + H )

• Type (?-s)(^.*\R)\1+ in the Find what: zone

• Type \1 in the Replace with: zone

• Select the Regular expression search mode

• Click on the Replace All button

• Finally, save this list of NON-duplicate lines

Et voilà !

Best regards,

guy038