See http://apple.stackexchange.com/a/102105/1860 for why
su does not work for all applications.
Recent versions of
launchd have the ability the launch applications within another user's session; although Apple engineers have not recommended its general use.
bsexec option in launchctl to target the appropriate user session:
bslist [PID | ..] [-j]
This prints out Mach bootstrap services and their respective states. While the namespace
appears flat, it is in fact hierarchical, thus allowing for certain services to be only avail-
able to a subset of processes. The three states a service can be in are active ("A"), inactive
("I") and on-demand ("D").
If [PID] is specified, print the Mach bootstrap services available to that PID. If [..] is
specified, print the Mach bootstrap services available in the parent of the current bootstrap.
Note that in Mac OS X v10.6, the per-user Mach bootstrap namespace is flat, so you will only
see a different set of services in a per-user bootstrap if you are in an explicitly-created
If [-j] is specified, each service name will be followed by the name of the job which regis-
bsexec PID command [args]
This executes the given command in the same Mach bootstrap namespace hierachy as the given
This prints a hierarchical view of the entire Mach bootstrap tree. If [-j] is specified, each
service name will be followed by the name of the job which registered it. Requires root priv-
The recommended approach is to write a launchd job ticket and restart the Mac - or ask the user to log-out and back in again.