Some standard environment variables are listed below:
Variable
Description
%TEMP%
Specifies the path to the temporary directory where the temporary
files are stored. Some applications don't delete their temporary files,
that is why you must clean this directory from time to time to free
up more space on your hard drive.
%WINDIR%
Specifies the location of the OS directory.
%WINSYS%
Specifies the location of the OS directory.
%USERPROFILE%
Specifies the path to the user profile (the profile stores all user
data, including settings of some applications).
%PROGRAMFILES%
Specifies the location of the Program Files folder.
%ALLUSERSPROFILE%
Specifies the path to the All Users Profile.
%APPDATA%
Specifies the path to the folder where the current user's application
settings are stored.