Rename all files in a directory with a Windows batch script

How would I write a batch or cmd file that will rename all files in a directory? I am using Windows.

Change this:

750_MOT_Forgiving_120x90.jpg
751_MOT_Persecution_1_120x90.jpg
752_MOT_Persecution_2_120x90.jpg
753_MOT_Hatred_120x90.jpg
754_MOT_Suffering_120x90.jpg
755_MOT_Freedom_of_Religion_120x90.jpg
756_MOT_Layla_Testimony_1_120x90.jpg
757_MOT_Layla_Testimony_2_120x90.jpg

To this:

750_MOT_Forgiving_67x100.jpg
751_MOT_Persecution_1_67x100.jpg
752_MOT_Persecution_2_67x100.jpg
753_MOT_Hatred_67x100.jpg
754_MOT_Suffering_67x100.jpg
755_MOT_Freedom_of_Religion_67x100.jpg
756_MOT_Layla_Testimony_1_67x100.jpg
757_MOT_Layla_Testimony_2_67x100.jpg

Solution

A FOR statement to loop through the names (type FOR /? for help), and string search and replace (type SET /? for help).

@echo off
setlocal enableDelayedExpansion
for %%F in (*120x90.jpg) do (
  set "name=%%F"
  ren "!name!" "!name:120x90=67x100!"
)

UPDATE - 2012-11-07

I've investigated how the RENAME command deals with wildcards: How does the Windows RENAME command interpret wildcards?

It turns out that this particular problem can be very easily solved using the RENAME command without any need for a batch script.

ren *_120x90.jpg *_67x100.*

The number of characters after the _ does not matter. The rename would still work properly if 120x90 became x or xxxxxxxxxx. The important aspect of this problem is that the entire text between the last _ and the . is replaced.