The sharing command is new to desktops, but not new to OSX. I've used it in shell scripts on a Snow Leopard (10.6) server. (It's very useful if you are creating or updating the permissions for hundreds of shares at once. The manual method is brutal, as you can imagine.)
Checking the Apple man pages, they show documentation for it on 10.7.4 and for 10.4-intel[1], so it's been around on the servers for some time. (Also, the man pages still list it as a server-only command. Those may not have been updated yet for Mountain Lion.)
(If you're not already aware of them, Apple has a very full set of man pages online. The framed browsing style is a pain, but the pages are still great for scanning and finding new commands[2].)
Checking the Apple man pages, they show documentation for it on 10.7.4 and for 10.4-intel[1], so it's been around on the servers for some time. (Also, the man pages still list it as a server-only command. Those may not have been updated yet for Mountain Lion.)
(If you're not already aware of them, Apple has a very full set of man pages online. The framed browsing style is a pain, but the pages are still great for scanning and finding new commands[2].)
[1] https://developer.apple.com/library/mac/#documentation/darwi...
[2]: https://developer.apple.com/library/mac/#documentation/darwi...