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.