I lately did a large update on my small wordpress site, thus some old permalink are invlid now.

Seach google for any tutorial about this and located a great deal about static html page redirection good examples or specific php page which aren't what i am searching for

Both my old and new permalinks have been in path format, for instance, i want redirect a few web addresses of old gallery posts (erased) that are

/2009/06/gallery/abc/
/2009/06/gallery/cba/
/2009/06/gallery/bbc/
/2009/06/gallery/aab/

to a different page that is

/gallery/

How do you write a proper redirect rule with this?

Try something similar to this:

RewriteEngine On
RewriteRule ^/2009/06/gallery/\(?([^/]*)\/$ /gallery/ [R=301,L]
RewriteRule ^[0-9]{4}/[0-9]{2}/gallery/.*$ gallery [R=permanent,L]

Should enable you to get to where you have to be. If you want the particular parameters (IE Date / Month / Title) passed along it's a little of the alter, but do-able.

EDIT Fixed typo.

Personally, I'd make use of the Redirection wordpress plugin instead of editing your .htaccess directly -- it's simpler, less danger-prone, and enables you to log what redirections happen to be happening. It will likewise track 404 errors so that you can find out if you've forgotten to redirect anything.

Then, if you are just redirecting a few fixed posts, it's only a matter of adding an easy rule for every redirect, using the old and also the new Web addresses, around the Redirection configuration page. You may also use regular expressions, just like .htaccess, if you wish to do anything whatsoever more difficult.