getenv/2
Module: builtins
getenv/2 — gets the value of the given os environment variable
FORMS
getenv(EnvVar, EnvVal)
DESCRIPTION
EnvVar, which must be instantiated, can be a symbol, an UIA, or a list of ASCII characters denoting an operating system environment or shell variable. The value of this external variable is accessed and an atom or a UIA composed of the corresponding list of ASCII characters is unified with EnvVal. If EnvVar is not defined in the os environment, getenv/2 fails.
EXAMPLES
?- getenv('TERM', Term) .
Term = xterm
yes.
?- getenv('PATH', Path).
Path = '.:/usr/local/bin:/usr/bin/X11:/usr/bin:/bin:/usr/ccs/bin'
yes.
?- getenv('FOOBAR', Foobar).
no.