batch script machine environment variables

Question

I have a windows batch script that gets the PATH environment variable, checks if it has some value in it, and then sets it back. For example:

SET CURRPATH=%PATH%
:: do some stuff to check for a value in CURRPATH and add the value in if it is not in there
setx PATH %PATH%

This works, but the problem is that something else I installed previously created a user system environment variable named PATH. When I access the %PATH% variable in my batch script, it concatenates both the user environment variable PATH and the machine environment variable PATH. Everytime I run the script the user variable PATH gets appended to the machine environment variable. Is there a way to just access the machine environment variable?

While I could simply remove the user environment variable PATH, this is not a good general solution since I cannot guarantee if the people running the script will have this same issue.

Note this seems to be specific to the PATH variable

Answer 1

There is at least one other problem with your approach: it will expand any environment variables present in PATH, which may be undesirable. Also you may find that setx occasionally hangs, I believe this is due to other applications not responding as expected when it broadcasts the change.

The best solution is probably to build an MSI file or use another well-developed installer technology.

Second best would be to write an application (a real application, not a batch script) to manipulate the registry setting holding the environment variable. The registry key containing the machine environment variables can be found here:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment

See also this question on SuperUser. There's an answer there which includes a batch-file-based solution, although it doesn't work reliably.