RoboCopy – Exclude existing files.cmd

robocopy.exe c:Sourcepath c:Destpath /E /XC /XN /XO

/E makes Robocopy recursively copy subdirectories, including empty ones.
/XC excludes existing files with the same timestamp, but different file sizes. Robocopy normally overwrites those.
/XN excludes existing files newer than the copy in the source directory. Robocopy normally overwrites those.
/XO excludes existing files older than the copy in the source directory. Robocopy normally overwrites those.

With the Changed, Older, and Newer classes excluded, Robocopy will exclude files existing in the destination directory.