How can I batch rename files using the Terminal?

Question

I have a set of files, all of them nnn.MP4.mov. How could I rename them so that it is just nnn.mov?

Answer 1

To test print the operation:

for file in *.MP4.mov; do j=`echo $file | cut -d . -f 1`;j=$j".mov";echo mv \"$file\" \"$j\"; done

To make it work:

for file in *.MP4.mov; do j=`echo $file | cut -d . -f 1`;j=$j".mov";mv "$file" "$j"; done