I'm working on some .bat stuff created in a legacy application, which uses many environment variables. I need to know exactly what is every one of them (%windir%, %os%, etc.).

So I need the official Microsoft Documentation about the System Environment Variables of Windows (at least from the NT version).

I've reading some sites with partial information (there are variables absent, such as %os%), so I really want to look at the Official info.

Searching with Google, Bing and inside the MSDN site give just reports about one or other variable, but no a comprehensive and centralized list of all.

Anybody knows where is that documentation available?

  • I would say there isn't one; any app can use any variables it likes. – Ignacio Vazquez-Abrams Dec 2 '10 at 19:04
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    @Néstor: Simply typing set in a command prompt lists quite a few, including all you mentioned. They all seem fairly easy to understand. – oKtosiTe Dec 2 '10 at 19:10
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  • Updated my answer to include a link too. – SgtOJ Dec 2 '10 at 20:07
  • +1 @moab - Posted the same link without noticing. Got it from Wikipedia? – SgtOJ Dec 2 '10 at 20:08

Site? Maybe not? Try this link. The list even breaks it down to what OS can use it. The variable will look a little different. That is only because it is missing the percent signs that are at the beginning and end.

Still not happy? Try this opening Command Prompt and type set and hit enter. It will list all the variables. As with the site listed above, the variable here will also look a little different.

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    That site doesn't seem to exist anymore – Brad Gilbert Feb 11 '13 at 17:35

While not official the best functional reference I've seen, that has been reliable and kept up to date for many years, is SS64 http://ss64.com/nt/syntax-variables.html. It includes undocumented variables and OS version specific info.


No complete list either but this link may already help to detect the OS you have: http://support.microsoft.com/kb/190899

Typing set in cmd.exe for getting a list of all really used variables on your system is known I assume?!

protected by Ramhound Mar 25 at 20:17

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