Windows Common Environment variables

%allusersprofile%
Lists the location of all user profile files.

%appdata%
Lists the default storage location for application data.

%cd%
Lists the current directory.

%clientname%
Lists the NetBIOS name of the client when joining to a Terminal Services session.

%cmdcmdline%
Lists the command lines used to start the current Cmd.exe.

%cmdextversion%
Command out the current command handler extension version number.

%commonprogramfiles%
Lists the folder paths for commonly used files.

%computername%
Lists the computer names.

%comspec%
Lists the paths to executable command shells (command handlers).

%date%
Lists the current date.

%errorlevel%
Lists the error codes for the most recently used commands.

%homedrive%
Lists the drive letter that resides with the user's home directory.

%homepath%
Lists the full path to the user's home directory.

%homeshare%
Lists the network path of the user's shared home directory.

Desktop
%homedrive%%homepath%\ Desktop

Start Menu:
%homedrive%%homepath%\"Start Menu

%logonsever%
Lists the name of the domain controller that is valid for the current logon session.

%number_of_processors%
Lists the number of processors installed on the computer.

%os%
Lists the name of the operating system. (windowsxp and Windows2000 are listed as Windows_NT.)

%Path%
Lists the search paths for the executable files.

%pathext%
Lists the file name extensions that the operating system thinks can be executed.

%processor_architecture%
Lists the processor's chip architecture.

%processor_identfier%
Lists the description of the processor.

%processor_level%
Lists the model number of the computer's processor.

%processor_revision%
The revision number of the processor is listed.

%ProgramFiles%
Lists the path to the ProgramFiles folder.

%prompt%
Lists the command prompt settings for the current command interpreter.

%random%
Lists the random decimal numbers bounded between 0 and 32767.

%sessionname%
Lists the connection and session name when connecting to a Terminal Services session.

%systemdrive%
Lists the drives where the Windows startup directory resides.

%SYSTEMROOT%
Lists the location of the Windows startup directory.

%temp% or%tmp%
Lists the default temporary directories for available applications for the currently logged-on user.

%time%
Lists the current time.

%userdomain%
Lists the name of the domain that contains the user account.

%USERNAME%
Lists the name of the user who is currently logged on.

%USERPROFILE%
Lists the current user profile location.

%WINDIR%
List the location of the operating system directory