The monks who responded above with 'C:/cFiles' were working on the fact that the MS Windows operating system itself will accept either / or \ as a directory separator. Unfortunately the same cannot be said of all applications, particularly those that indicate command-line options by the / prefix, and dir is one of them.
. If you are going to use badly behaved programs like the Micrsoft ones (!) then best to use \, but remember to add an extra one:
.