Linux and Renaming Multiple Files

Personal Note: If you want to mass rename a collection of files via the shell in linux, do as shown here or here. I. e. feed some regular expressions to the rename command followed by a filter which selects the files. Just like so:

rename oldname newname *.files

Or in my use case a follows:

rename s/JPG/jpg/ *.JPG
rename s/DSC/DSD/ *.jpg