Setting a system environment variable from a Windows batch file?

Question

Is it possible to set a environment variable at the system level from a command prompt in Windows 7 (or even XP for that matter). I am running from an elevated command prompt.

set name=value seems to be only valid for the session of the command prompt..

Answer 1

The XP Support Tools (which can be installed from your XP CD) come with a program called setx.exe:

C:\Program Files\Support Tools>setx /?

SETX: This program is used to set values in the environment
of the machine or currently logged on user using one of three modes.

1) Command Line Mode: setx variable value [-m]
   Optional Switches:
    -m  Set value in the Machine environment. Default is User.

...
For more information and example use: SETX -i

I think Windows 7 actually comes with setx as part of a standard install.