Remove file extension in OS X using Terminal

Question

Problem:

I have some 200+ files named something in line with "DSC01852.JPG.jpg". I would like to remove the file extension so the result becomes "DSC01852.JPG".

Any suggestions? I looked at the mv command but couldn't quite figure out how to write the correct command.

Solution

If these files are all in the same directory you can rename them like this:

for f in /some/dir/*.JPG.jpg; do
  mv "$f" "${f%.*}"
done

${f%.*} removes shortest text matching the pattern .* (a dot followed by arbitrary text) from the end of the variable $f (in this case the file name), thus producing commands like the following:

mv "/some/dir/DSC01852.JPG.jpg" "/some/dir/DSC01852.JPG"