Mac OS X Tiger in a Nutshell

Adding Users to a Group

You can add users to the group by appending values to the users property with dscl’s merge command at the command line (or by using the merge command interactively; start dscl in interactive mode with sudo dscl .). If the users property does not exist, dscl creates it. If the users are already part of the group, they are not added to the list (contrast this with the -append command, which can result in the same user being added more than once if the command is invoked multiple times):

    $ sudo dscl . merge /groups/writers users bjepson rothman