I needed to copy only missing files from a volume shadow copy back to a clients share after clearing out crypto malware encrypted files, and I found a new favourite command:
subst drive1: drive2:path
Substitutes a path for a drive letter, for example:
subst x: c:\users\adam\desktop
maps x: to my desktop in my profile.
Where this came in particular handy for me we using robocopy to restore files an folders out of a volume shadow copy (previous version).
I wanted to run robocopy a: b: /xc /xn /xo /s which only copies missing files, and does not copy existing files – regardless of age or difference, to extract missing files from the shadow copy.
So first I found the path to the file by right clicking on a file in the shadow copy and copying the location then running subst:
subst x: "\\localhost\C$\@GMT-2016.10.24-14.01.30\Server Shares\Company"
I could then run my robocopy from the x: drive.
Finished off with subst x: /d to remove the drive mapping.
Useful write up here:
https://chaoliu12.wordpress.com/2013/02/11/restore-files-from-shadow-copy/
And subst technet article here: