Robocopy (originally called Robust File Copy Utility) has been around a long time–since the Windows NT 4.0 Resource Kit if I remember correctly. This command-line tool has been enhanced over the years and is an in-box utility in recent versions of Windows. One way that copying files with Robocopy differs from doing it with Windows Explorer is that Robocopy doesn’t enumerate the size and number of files to be copied before beginning the copy operation. By contrast, the Windows Explorer file copy dialog tries to estimate how long it will take to copy your files, sometimes without success as this classic XKCD comic illustrates:
http://www.wservernews.com/go/1374754468569
Anyways, what if you want to use Robocopy to copy some files but before you do so you want to get some idea of how much data will be copied? On Windows 8 and Windows Server 2012 you can do this by running the following Robocopy command:
Robocopy/E /NFL /NDL /MT /L
This command will perform a multithreaded scan of the contents of the source directory without actually copying any files to the target directory. You can then re-run the command without the /L switch to actually perform the copy operation.
Note that this command also works on earlier versions of Windows, but the execution is single-threaded on those platforms, which means enumeration can take longer.
The above tip was previously published in an issue of WServerNews, a weekly newsletter from TechGenix that focuses on the administration, management and security of the Windows Server platform in particular and cloud solutions in general. Subscribe to WServerNews today by going to http://www.wservernews.com/subscribe.htm and join almost 100,000 other IT professionals around the world who read our newsletter!
Mitch Tulloch is an eleven-time recipient of the Microsoft Most Valuable Professional (MVP) award and a widely recognized expert on Windows Server and cloud computing technologies. Mitch is also Senior Editor of WServerNews. For more information about him see http://www.mtit.com.
