Suppose you have this file:
x
a
b
c
x
x
a
b
c
x
x
and you want to find the sequence abc (and select the whole 3 lines) with Notepad++ . How to express the newline in regex, please?
Notepad++ can do that comfortably, you don't even need regexes
In the find dialogue box look in the bottom left and switch your search mode to Extended which allows \n etc.
As odds on you're working on a file in windows format you'll be looking for \r\n (carriage return, newline)
a\r\nb\r\nc
Will find the pattern over three lines
Update 18th June 2012
With the new Notepad++ v6, you can indeed search for newlines with regexes. So you can just use
a\r\nb\r\nc
even with regular expressions to accomplish what you want. Note \r\n is Windows encoding of line-breaks. In Unix files, its just \n.
Unfortunately, you can't do that in Notepad++ when using regex search. Notepad++ is based on the Scintilla editor component, which doesn't handle newlines in regex.
You can use extended search for newline searching, but I don't think that will help you search for 3 lines.
More info here.
Update: Robb and StartClass0830 were right about extended search. It does work, but not when using regular expressions search.
^a\x0D\x0Ab\x0D\x0Ac
This will work \x0D is newline and \x0A is carriage return. Assumption is that each line in your file ends with ascii 10 and 13.
I found a workaround for this.
Simply, in Extended mode replace all \r\n to a string that didn't exist in the rest of the document eg. ,,,newline,,, (watch out for special regexp chars like $, &, and *).
Then switch to Regexp mode, do some replacements (now newline is ,,,newline,,,).
Next, switch to Extended mode again and replace all ,,,newline,,, to \r\n.
a\r\nb\r\nc works for me, but not ^a\x0D\x0Ab\x0D\x0Ac
Hmm, too bad that newline is not working with regular expressions. Now I have to go back to Textpad again. :(
In Notepad++ you can also try highlighting the desired part of the text and then pressing CTRL+J.
That would justify the text and thus removing all line endings.
来源：https://stackoverflow.com/questions/4398613/notepad-newline-in-regex