Regular Expression to Remove Subdomain from Root Domain in List - Notepad++ or Gvim
notepad++, regex, vim
Solution
A couple of ways of doing it for Vim (the trailing slashes are optional, too):
:%s/^.\+\.\ze[^.]\+\.[^.]\+$//
:%s/^.\+\.\([^.]\+\.[^.]\+\)$/\1/
See also `:help /\ze` etc. `\ze` and `\zs` are Vim-specific and very useful. There are also look-ahead and look-behind assertions which can be useful, in Vim and PCRE.
I believe Notepad++ uses PCRE; find `^.+\.([^.]+\.[^.]+)$` and replace it with `\1` should work (but I don't use Notepad++).
Be aware this won't work well with country code top level domains which use third-level registration - `example.com.au` would be turned into `com.au`. And then there are some countries which use second- or third-level registration under certain rules... if you care about those cases, you'll need more rules and a full parser would be neater than a regular expression (though as always it would be possible with regular expressions).
Problem
I have a list of URLs stored in a .txt file (I'm using Windows 7). The format of the URLs is this: ``` somesite1.com somesite2.com somesite3.com sub1.somesite3.com sub2.somesite3.com sub3.somesite3.com sub1.somesite3.net sub1.somesite1.org ``` In notepad++, there is an option to use "find-replace with regular expressions", and I'm fairly sure that gvim allows the user of regular expressions (although I'm not entirely sure how to use them in Gvim). Anyway, I don't know what to put in the find & replace boxes so it can go through the contents of the file and leave me with only the root domains. If done properly, it would turn the above example list into this: ``` somesite1.com somesite2.com somesite3.com somesite3.com somesite3.com somesite3.com somesite3.net somesite1.org ``` Can somebody help me out?