1ENV
2---
3
4Operator to read environment variables.
5
6Use the syntax ``$ENV{VAR}`` to read environment variable ``VAR``.
7
8To test whether an environment variable is defined, use the signature
9``if(DEFINED ENV{<name>})`` of the :command:`if` command.
10
11See the :command:`set` and :command:`unset` commands to see how to
12write or remove environment variables.
13