Managing environment variables

Defining environment variables

There are three places in MDT where environment variables can be defined:

• Workbench - global definitions for the whole workspace
• Runtime - definitions for selected runtime - in Emacs environment they relate to variables defined in the environment file
• Session - definitions for selected session - in Emacs environment they relate to variables defined in the GIS alias

Besides, these places variables can also be defined in operating system. In each case the variables collection can be created in two ways by:

• adding environment variables one by one using Environment Variable dialog
• importing the existing set of environment variables from environment file or GIS aliases file using Import Environment dialog

Note that the order of the variables is significant. The variables may be moved up and down in the collection by means of provided buttons.

Evaluating environment variables

When session is started environment variables are evaluated (resolved) - a new set of environment variables is created. The set is used then to run the session. The way of creating the set of variables depends on the session type.

Environment variables may be overridden - when the same environment variable is defined in two or more places with a different value, the value at the lowest level (last to evaluate) is finally set.

Unresolved environment variables

When session is run unresolved environment variables are presented to user in a special dialog. User may decide whether to continue session start or to cancel it.

Environment Preferences
Runtime Environment
Session Environment
Session Link Environment
Import Environment Dialog