ENVIRON$ Function Details
 
Syntax
  ENVIRON$ (environmentstring)
  ENVIRON$ (n)
 
The environmentstring is a string constant or variable containing
the name of an environment variable. The argument n is a numeric
expression.
 
If you specify an environmentstring name, but it cannot be found in
the environment-string table, or there is no text following it, then
ENVIRON$ returns a null string. Otherwise, ENVIRON$ returns the text
following the equal sign in the environment-string table.
 
If you specify a numeric argument (n), the nth string in the
environment-string table is returned. In this case, the string
includes all of the text, including the environmentstring name.
If the nth string does not exist, ENVIRON$ returns a null string.
The n argument can be any numeric expression; it is rounded to an
integer.