Was helping setup a VM/NFS share on a friends OSX machine using all_squash to remap the UID and GID. Unfortunately OSX doesn’t like using the /etc/group file as traditional linux, doesn’t provide uid and gid commands or the Netinfo utility. So to cut to the chase, to list the UIDs of the local users:

dscl /Local/Default -list /Users UniqueID

I’m sure altering the last “UniqueID” value (as it’s referred to as a ‘key’) will yeild more interesting info, this is left as an excercise to the reader