I have several directories with the format of the year, month, and day followed by a description of the event. For example: "2012 05 26 - EventA", "2012 05 26 - EventB". What I would like to do is rename all these directories so that the spaces between the numbers in the date are replaced with dashes. Thus, "2012 05 26 - EventA" becomes "2012-05-26 - EventA". I know I can do this one folder at a time with the mv command, but is there a way to do this in a batch process with wildcards somehow?