Operating System Environment Variables

(getenv name) gets the value of an operating system environment variable (Unix and Windows). The name argument is a string that does not contain a null character; if an environment variable name exists, its value is returned (as a string); otherwise, #f is returned.

(putenv name) sets the value of an operating system environment variable (Unix and Windows). The name and value arguments are strings that do not contain a null character; the environment variable name is set to value. The return value is #t if the assignment succeeds, #f otherwise.