Is their a way for a Child process to modify its Parent's environment?

[Steven Schveighoffer via Digitalmars-d-learn]

On Tue, 24 Jun 2014 21:53:51 -0400, WhatMeWorry <kc_heaser at yahoo.com>  
wrote:

> I open a command line window, and run the following 6 line program
>
> void main()
> {
>     string envPath = environment["PATH"];
>
>     writeln("PATH is: ", envPath);
>
>     envPath ~= r";F:\dmd2\windows\bin";
>
>     environment["PATH"] = envPath;
>
>     envPath = environment["PATH"];
>
>     writeln("PATH is: ", envPath);
>
> }
>
> It prints out the following
>
> PATH is: C:\Windows\system32;C:\Windows...
> PATH is: C:\Windows\system32;C:\Windows...F:\dmd2\windows\bin
>
> when the program exits, I'm back at the command line and I do a
>
> echo %PATH%
>
> which just shows C:\Windows\system32;C:\Windows...
>
> Anybody know of a way to make the change stick for the lifetime of the
> command window?

Only the command shell can change it's own environment. When you execute  
commands that set an environment variable, those are shell builtins, not  
external programs.

You can run a batch file (which is not run in a separate process) which  
sets environment variables. This may be the only way to affect the  
environment. Basically, have a program run that dictates what to set,  
builds a batch file, then run that batch file from the command line. This  
could be done in another batch file.

-Steve