I would like to use underscore in my permalinks instead of hyphen.

Current permalink:

www.example/2013/01/hello-this-is-a-test-post/

Desired permalink

www.example/2013/01/hello_this_is_a_test_post/

I have tried some solutions mentioned here in stacexchange. But they were not working.

I would like to use underscore in my permalinks instead of hyphen.

Current permalink:

www.example/2013/01/hello-this-is-a-test-post/

Desired permalink

www.example/2013/01/hello_this_is_a_test_post/

I have tried some solutions mentioned here in stacexchange. But they were not working.

• functions
• permalinks
• filters
• actions
• pluggable

• 1 what about writing a script to change the slug of every post? – Mridul Aggarwal Commented Jan 5, 2013 at 16:14
• Dashes seem to be the more reliable word separator from what I can tell. Why are you doing this? – s_ha_dum Commented Jan 5, 2013 at 16:24
• 1 Which some solutions? And note Google treats - as word separator, but not _. You will hurt yourself. :) – fuxia ♦ Commented Jan 5, 2013 at 16:24
• @toscho I've tried this one. If google doesn't treat underscore as word separator, why does some popular sites use it?. Example wikipedia link. Example wordpress codex link – PrivateUser Commented Jan 5, 2013 at 16:41
• @s_ha_dum underscore looks more pretty than hyphen. Example wikipedia link – PrivateUser Commented Jan 5, 2013 at 16:44

3 Answers 3

it can be done easily without any codes or plugin just go to pages dashboard, click Quick Edit" which url you want to change. Now add underscore. Update and done

Toscho advised me like this.

Google treats - as word separator, but not _. You will hurt yourself. :)

He was 100% true. Here is an article that explains it. So I dropped the idea.

But if you still looking for a solution here is the answer.

Answered by this stackoverflow user

Hunt down the following file: wp-includes/formatting.php

Jump down to the sanitize_title_with_dashes function. You'll find this section of code inside:

$title = strtolower($title);
$title = preg_replace('/&.+?;/', '', $title); // kill entities
$title = str_replace('.', '-', $title);
$title = preg_replace('/[^%a-z0-9 _-]/', '', $title);
$title = preg_replace('/\s+/', '-', $title);
$title = preg_replace('|-+|', '-', $title);
$title = trim($title, '-');

Swap out all of the dashes/hyphens (-) for underscores (_) like so:

$title = strtolower($title);
$title = preg_replace('/&.+?;/', '', $title); // kill entities
$title = str_replace('.', '_', $title);
$title = preg_replace('/[^%a-z0-9 _-]/', '', $title);
$title = preg_replace('/\s+/', '_', $title);
$title = preg_replace('|-+|', '_', $title);
$title = trim($title, '_');

Note that any posts you've created before this change, and rely on the %postname% permalink structure tag, will be broken.

In that case you'll need to go back and republish those post so the dashes are swapped out for the underscores. Or just write yourself a little SQL to replace them.

I initially did this but with every update to Wordpress I'd have to make the manual change again, so I made this plugin in case it helps anyone: http://wordpress/plugins/underscores-in-permalinks/