Commonly used environment variables
An environment variable is a variable that describes the operating environment of a process and typically includes information about the home directory, command search path, the terminal in use, and the current time zone. Setting an environment variable is optional. If a variable is not set, it will not have any value. This topic contains a partial list of _BPX, _BPXK, and _CEE environment variables.
For information about environment variables used by a particular command, read the description of that command. For more information about environment variables that are used by the C-RTL, see Environment variables specific to the z/OS XL C/C++ library in z/OS XL C/C++ Programming Guide.