I had the problem of numerous Amazon widgets on this site having a different link color (#0000FF) than the one used for the theme (#3478E3).

Not wanting to go through each post and modifying the widget link color codes by hand, I Googled for Find / Search and Replace solutions designed specifically for Wordpress.

Two plugins in particular seemed promising:

The Search Regex plugin looked promising, with a user-friendly interface that shows you a preview of what will be replaced, and allows you to go ahead and perform the replacement, or edit the results in-place.

Unfortunately, a comment by John Godley indicated that the plugin didn’t support Wordpress 2.8 at the time.

I had no choice but to give the second plugin, Search & Replace, a try. It has an appropriate warning:

This plugin uses an standard SQL query so it modifies your database directly!
Attention: You cannot undo any changes made by this plugin. It is therefore advisable to backup your database before running this plugin. No legal claims to the author of this plugin! Aktivate the plugin only, if you want to use it!

Text search is case sensitive and has no pattern matching capabilites. This replace function matchs raw text so it can be used to replace HTML tags too.

The warning text links to a tutorial written by the author himself on using PHPMyAdmin to back the database up (Google’s English translation), but I just used the WordPress Database Backup plugin to perform the task instead.

Next, I went to Settings > Search & Replace in the Wordpress admin panel to fill out the relevant parameters. I checked the Content box, entered 0000FF in the Replace box, and 3478E3 in the with box. When I clicked on the Go button, there find & replace launched with no further prompting or warning.

(click to view a larger image)
Frank Bültge's Search & Replace Wordpress Plugin - Parameters

I was relieved that the search & replace ran successfully, and here’s what the final completion message looked like.

Search & Replace Wordpress Plugin - Completed