Add text and rename multiple files

Question

Okay, I have a lot of subfolders. Each subfolder contains some files. In each subfolder I want to add som text in the end of one file with the extension "tbn". The file name is not the same in each folder. Then I also want to change/rename the extension to jpg. See my example below

rename "myfile.tbn" to "myfile-poster.jpg"

I would like to do this from the command promt or from a batch file.

Have googled some of this. I would say my problem is to add the text in the end of the file "-poster" when the orginal filename varies.

Answer 1

You can find a file with an unknown name with a plain for loop (see for /? for details).
/R makes it recursive (searching through subfolders too)
the %%~n modifier returns the base filename only (no extension)

for /R %%A  in (*.tbn) do ECHO ren "%%A" "%%~nA-poster.jpg"

Remove the ECHO after verifying it does what you want to actually enable the ren command.