Repair permissions has been removed since 10.11 if I recall correctly.
Repair permissions only fixed permissions declared in package receipts (installers create them with specific permission settings).
I think there was a repair_packages tool but that also disappeared, this page has a third party alternative…
https://www.firewolf.science/2016/07/repairpermissions-v3-now-supports-repairing -permissions-on-macos-sierra/
Apple claim that SIP prevents the installed permissions changing, so there should be no need to actually repair them anymore.
Repair disk permissions with Disk Utility - Apple Support
The repairUserPermissions was a feature of the recovery partition, it has existed for years but has recently moved to the OS. It is specific to user account permissions, not system permissions. It requires the '/' argument because users can store their user account on another disk, so the home folder may be at another /Volumes/path.
The second section covers repair user permissions in recovery mode…
http://osxdaily.com/2011/11/15/repair-user-permissions-in-mac-os-x-lion/
Please read the manuals if you try those commands or post more info on what you hope to achieve via these commands. Repair permissions can often be treated as a panacea to cure all ills when it may not be relevant.