For decades, Linux users have been renaming files with the mv command. It’s easy, and the command does just what you expect. Yet sometimes you need to rename a large group of files. When that is the case, the rename command can make the task a lot easier. It just requires a little finesse with regular expressions.
Unlike the mv command, rename isn’t going to allow you to simply specify the old and new names. Instead, it uses a regular expression like those you’d use with Perl. In the example below, the “s” specifies that we’re substituting the second string (old) for the first, thus changing this.new to this.old.