Environment variables are frequently used in conjunction with command line applications, and can be read as using the getenv() function of the CRT. For example:

CRTLibrary default getenv: 'TZ'

 

The result is a String (in this case the name of the current timezone).

New environment variables can be added, the value of existing variables changed, or variable removed, using the _putenv() function.

CRTLibrary default _putenv: 'Dolphin=Cool'.

CRTLibrary default getenv: 'Dolphin'

 

See Microsoft's documentation for further details of _putenv().