The syntax for the rename command is:
rename [ -v ] [ -n ] [ -f ] perlexpr [ files ]
-v means “verbose” and it will output the names of the files when it renames them. It is a good idea to use this feature so you can keep track of what is being renamed. It is also a good idea to do a test run with -n which will do a test run where it won’t rename any files, but will show you a list of files that would be renamed.
via How to Bulk Rename Files in Linux (Terminal or GUI) | Webmaster Tips.