On a Mac you can set a temporary environment variable using the Terminal application. This is easy to do and is worth doing before going to the trouble of setting one permanently. The process is further complicated because the syntax you use differs depending on the type of shell (csh, bash, tcsh).
1.Start a Terminal (Applications - Utilities - Terminal) and enter:
2.If you are running a bash or ksh shell, enter:
3.If you are running a csh or tcsh shell, enter:
setenv lightmap_LICENSE /Shared/lightmap/licenses/hdrlightstudio.lic
In the above example, the environment variable (lightmap_LICENSE) only exists in this shell. If you open another terminal, you would need to set the environment variable in that shell too.
For a more permanent solution, you'll need to add the environment variable to /etc/launchd.conf and for that you'll need to find your busy systems administrator.