How to Batch rename a part of a file name?

[DaviDaVinci]

This is in reference to Yahoo Messenger History folder.

Each of my contacts has a folder and in that folder is a file that has a filename like this.

20050414-myusername.dat

I'm planning on changing my username to something else but want to keep all the logs viewable through Yahoo. Essentially I want to migrate my logs to a new username.

How can I change the 'myusername' part to another name for all the files in all of the contacts folders at once?

Or is there a better way?

Want to do the same for MSN Messenger

 

[kamper]

Perl? I'll write the pseudocode but I'm guaranteed to get the syntax horribly messed up so someone else can fill that out.

 

[bersl2]

sed for Windows (or some other port of sed) used in a batch file will probably work.

 

[imported_BadKarma]

I use Irfanview as my default image viewer and it has a pretty good batch rename/conversion utility.
Link to Irfanview ->
http://www.irfanview.com/

 

[igowerf]

I use a program called Flexible Renamer.
http://hp.vector.co.jp/authors/VA014830/english/FlexRena/

It supports regular expressions so you can do some pretty powerful renaming.

 

[DaviDaVinci]

Rename Master

Looks good but scared to use it

 

[nweaver]

Google for Bulk Rename Utility, single executable and works well for windows. Perl would work well, and is what I would use on Linux, but I have issues with Perl in Windows

 

[cubby1223]

Or you can just use the rename command from a cmd window. In that situation would be:
ren *.dat ?????????newusername.dat