I tested this on a folder with about a half a million extremely random files from a very old system I cleaned off. I wanted to see how much space was saved but right clicking on the folder was brutally slow.
This was super fast. Ridiculously fast.
robocopy /l /nfl /ndl c:\folder \\localhost\C$\nul /e /bytes
Source article is using powershell to pretty up the info, but the function listed didn’t work, so i just ran the powershell command. Information was at the bottom so easy enough to do my own prettification.
Total Copied Skipped Mismatch FAILED Extras
Dirs : 3704 3704 0 0 0 0
Files : 452585 452585 0 0 0 0
Bytes : 192119912385 192119912385 0 0 0 0
Then easy enough to just divide to get the number at the command line like
192119912385/1024/1024/1024 to get
178.925611437298 in GB. You may prefer to just divide by 1000s instead of 1024. Dealer’s choice. =)