An array containing the values of the environment variables. The array is indexed by variable name, each element being the value of that variable. Thus, the environment variable HOME would be in ENVIRON["HOME"]. Its value might be `/u/close'. Changing this array does not affect the environment seen by programs which gawk spawns via redirection or the system function. (This may change in a future version of gawk.) Some operating systems do not have environment variables. The array ENVIRON is empty when running on these systems.