Mel: Internal Global Variables
From wikinotes
env
The command env lists all of maya's default environment variables. For example, one of the entries is $gPanelLabels
print $gPanelLabels
getenv
Query one of maya's environment variables. For example, to get the locations where maya checks for scripts:
getenv MAYA_SCRIPT_PATH ;
other useful tricks
get maya version
getApplicationVersionAsFloat
