Search and Replace - Remove specific IP ranges

Cranky Penny

Fellow Notepad++ Users,

Could you please help me the the following search-and-replace problem I am having?

I have rows of IP addresses with multiple IPs listed and I need to remove all entries in every row that begin with 172.* 128.* or fe*

Here is the data I currently have (“before” data):

172.16.0.1, 156.1.1.1, 127.0.0.1, fe20::250:90fd:fec5:7a2d, ::1
172.16.0.1, 172.1.1.1, 10.1.1.1, 127.0.0.1, fe20::250:90fd:fec5:7a2d, ffe20::250:90fd:fec5:7a2d, fe20::250:90fd:fec5:7a2d, ::1
172.15.0.1, 10.1.1.1, 127.0.0.1, fe20::250:90fd:fec5:7a2d, ::1
172.15.0.1, 10.1.1.1, 127.0.0.1, fe20::250:90fd:fec5:7a2d, ::1
172.12.0.1, 172.1.1.1, 10.1.1.1, 127.0.0.1, fe20::250:90fd:fec5:7a2d, ::1

Here is how I would like that data to look (“after” data):

156.1.1.1
10.1.1.1
10.1.1.1
10.1.1.1
10.1.1.1

Thanks for your time

Mark Olson

What you say you want doesn’t quite match what you appear to want, based on your before and after.

In any case, this should work:

go to the find/replace form (Ctrl+H assuming normal keybindings)
set the Search Mode to Regular expression

Find what: (?-i)(?:\b(?:(?:172|12[78])\.|ff?e)\S*,\x20*)|,\x20::1
Replace with: nothing (leave that box empty).

You’ll have to hit the Replace All button twice.

This isn’t really a particularly clever or complex regular expression, although it may appear daunting. Some notes:

the (?-i) makes the regex case-sensitive
the (?: and matching ) are just grouping parentheses that don’t capture
the \b matches a “word border” (that is, the border between a word character and a non-word character)
\S* matches zero or more non-whitespace characters
\x20 matches a normal space character.