environ

Functions
environment-variable name
environment-variables
(setf environment-variable) value name &optional (replace t)
environment-variables   [Function]
Return all environment variables as an associated list.
List elements are cons cells of the form

     (NAME . VALUE)

where NAME and VALUE are the name respective value of an
environment variable.
environment-variable  name  [Function]
Return the value of the environment variable NAME.
Value is nil if no entry with key NAME exists.
(setf environment-variable)  value name &optional (replace t)  [Function]
Set the value of the environment variable NAME to VALUE.
If the environment already contains an entry with key NAME
 and optional argument REPLACE is true (this is the default),
 replace the entry with key NAME.  Otherwise, do nothing.
If VALUE is nil, remove the entry with key NAME from the
 environment.