Hi,
Here is a sample command line:- "robocopy X:\Source Y:\Destination *.* /S /NP /XO >> logfile.txt"

What this does is:

•Copies all files from the source to the destination (noted by the *.*)
•/S - include subdirectories
•/NP - hides the progress (if you’re going to log to a file, you want this option)
•/XO - exclude files that are older/have not changed
•>> - appends the results to the file. If you only use one ‘>’, it will overwrite instead

and a link to a good article http://www.sqlmag.com/article/sql-server/tool-tip-the-awesomeness-of-robocopy.aspx

>Thanks for the info Neil, I shall have to get my head around it and see how I can use the robocopy command.