getenv get the value of an environment variable

## Syntax

    env=getenv(str [, defaultReturn] )

## Arguments

str

  character string specifying environment variable name

defaultReturn

  an optional character string. When this optional value is used, the function `getenv` returns the value `defaultReturn` when the environment variable `str` is not found.

env

  character string which contain the environment variable value

## Description

Return the value of an environment variable if it exists.

## Examples

    getenv('SCI')
    getenv('FOO','foo')