I wish to change my permalinks from /%year%/%monthnum%/%day%/%postname%/ to /%postname%/

however when I added the next towards the .htaccess file, posts did not redirect generate an income thought they'd:

RedirectMatch 301 /dddd/dd/dd/(.*) /$1

What should i put in my .htaccess file to really make it work?

My website is http://SweatingTheBigStuff.com

You do not get into any code to alter permalinks that's altering Wordpress core files, you'll break things and you will loose your changes with an upgrade. It's much simpler than that: visit Wordpress/Dashboard/Setings/Permalinks. In case your .htaccess is not writable, you will get an alert.

And, only using the postname in permalinks isn't suggested for performance reasons: Using only Postname in Permalinks « WordPress Codex

I believe everybody is missing the purpose here - I believe @Daniel has transformed his permalinks, and today really wants to redirect old permalinks.

The issue is your RedirectMatch regex is just matching a literal 'd', not numbers.

Personally I'd make use of this rather

RedirectMatch 301 ^/[0-9]{4}/[0-9]{2}/[0-9]{2}/(.+)$ /$1

However, @songdogtech is appropriate in stating that you will find difficulties with with the postname.

Another response to TheDeadMedic,

You could utilize a wordpress plugin known as Redirection to rerouted your old permalinks to new permalinks.

But when you have to improve your permalinks in the old version to a different version, then follow songdogtech's advice

You need to use wordpress after sales to update the permalinks (and when permissions allow, htaccess) is situated here:

http://SweatingTheBigStuff.com/wp-admin/options-permalink.php

as well as in custom structure put

/%postname%/

Save it and you're simply done