Permanently altering a user's %PATH% environment variable via batch or Python

Question

I've been having difficulty with getting my users to set the PATH environment variable manually, I'm looking for a way to do this automatically. A batch file would be preferable, since that would require them to run it themselves (with a warning as to what they're doing), but an addition to the setup.py is acceptable as well.

Other information: SET only affects the current and derivative shells; the permanent values seem to be stored in the Registry somewhere (a place where I dare not tread).

Answer 1

I just ran across this question and didn't like any of the available options so I decided to write my own solution.

(SetEnv would've been good, but I didn't like the non-libre license and I always prefer not having to call a subprocess... I wouldn't mind calling SetEnv as a subprocess but, according to Wikipedia, the license it uses is non-libre because it has some kind of "do no evil" clause and that kind of legally-ambiguous restriction is always a ticking time-bomb in my opinion.)

Here's a little MIT-licensed Python class to hide away the work of modifying the registry directly and sending the WM_SETTINGCHANGE. (Good for use in setup.py)

Answer 2

So, since I've been having difficulty with getting my users to set the PATH manually, I'm looking for a way to do this automatically.

The HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths (as well as HKEY_CURRENT_USER\...) registry key allows you to attach an application specific path to your executable name.

Whenever an executable of the given name is started, the application specific path is added to that executable's PATH environment variable.