What standard for Regular Expressions is Notepad++ using?

Tony De Groot

Hi,
I have been using Notepad++ for occasional general editing for a couple of years, and find it very useful.

I am starting to explore regular expressions but I have no reference for the regular expression terms or syntax. Can someone point me at a reference for the regular expressions used in Notepad++?

My baseline for Regular Expressions is on Edit/1000 under RTE/A for HP Minicomputers (1985) and early HPUX, but nothing for the last 20 ish years as I only dabble in Unix/Linux … I saw the syntax change quickly in the early days but do not know if it has stabilised into a common format by now …

Thanks,
Tony.

Scott Sumner

You will find an exhaustive discussion of the Notepad++ regular expression “flavor” here:
https://notepad-plus-plus.org/community/topic/9703/is-it-planned-to-switch-to-pcre2

Perhaps that contains a deeper treatment than you want/need. Basically N++ currently uses the BOOST implementation, and these TWO links, which are buried in the above link, are very helpful in understanding Notepad++'s regexes:

SEARCHING:
http://www.boost.org/doc/libs/1_55_0/libs/regex/doc/html/boost_regex/syntax/perl_syntax.html

REPLACING:
http://www.boost.org/doc/libs/1_55_0/libs/regex/doc/html/boost_regex/format/boost_format_syntax.html

Tony De Groot

Hi Scott,

Thanks for the help.

I have all my editting done except for deleting lines.

From the command line I would use something like:
1$f/^“”/,d
to search the file, find all occurrences of 2 quotes at the start of a line, and then delete that line. Repeat until end of file.

I cannot see if there is a facility to drop into a command line, nor can I find a delete option in the Search/Replace menu.

Can you tell me what I am missing?

Thanks,
Tony

guy038

Hello Tony,

You can get this action, by two means, with Notepad++ :

by performing a simple Search and Replace operation, in regular expression mode
by deleting all the bookmarked lines, which contain two double quotes, at the beginning of each line

First method :

Open the Replace dialog ( CTRL + H )
SEARCH ^"".*\R
REPLACE Nothing
Check the Wrap around option
Check the Regular expression search mode ( Important )
UNCHECK the .matches newline option, if necessary
Click on the Replace All button

Notes :

^ is an assertion, that represents the location between the last EOL character of the previous line and the first character of the current line
.* then matches the rest of the line, after the two double quotes
\R stands for any kind of EOL characters ( \r\n, for Windows files, \n, for Unix files or \r for old Mac files )
As the replacement zone is empty, then, the entire lines, containing "", at beginning of lines are deleted

Second method :

Open the Mark dialog ( Menu Search - Mark… )
SEARCH ^""
Check the Bookmark line option
Check the Wrap around option
Check the Regular expression search mode ( Important )
UNCHECK the .matches newline option, if necessary
Click on the Mark All button
Select the menu option Search - Bookmark - Cut Bookmark Lines

Best Regards,

guy038

Tony De Groot

Hi guy038,

I had used part of your first example - I used search for ^“”, but missed the rest of the line. Using the complete expression worked fine.

Many thanks,

Tony