Windows environment variables

This is a list of Windows environment variables / Windows system variables.

See also changing / adding environment variables to see how to manipulate these values or add your own (silently).

ALLUSERSPROFILE	Local returns the location of the All Users Profile.
APPDATA	Local returns the location where applications store data by default.
CD	Local returns the current directory string.
CMDCMDLINE	Local returns the exact command line used to start the current cmd.exe.
CMDEXTVERSION	System returns the version number of the current Command Processor Extensions.
COMPUTERNAME	System returns the name of the computer.
COMSPEC	System returns the exact path to the command shell executable.
CommonProgramFiles	Returns the location of the Common Files directory.
CommonProgramFiles(x86)	Returns the location of the Common Files directory for 32-bit applications on Windows 64-bit.
CommonProgramW6432	Returns the location of the Common Files directory for 64-bit applications on Windows 64-bit, if running a 32-bit application.
DATE	System returns the current date. This variable uses the same format as the date /t command. Cmd.exe generates this variable. For more information about the date command, see the Date command.
ERRORLEVEL	System returns the error code of the most recently used command. A non-0 value usually indicates an error.
HOMEDRIVE	System returns which local workstation drive letter is connected to the user's home directory. This variable is set based on the value of the home directory. The user's home directory is specified in Local Users and Groups.
HOMEPATH	System returns the full path of the user's home directory. This variable is set based on the value of the home directory. The user's home directory is specified in Local Users and Groups.
HOMESHARE	System returns the network path to the user's shared home directory. This variable is set based on the value of the home directory. The user's home directory is specified in Local Users and Groups.
LOGONSERVER	Local returns the name of the domain controller that validated the current logon session.
NUMBER_OF_PROCESSORS	System specifies the number of processors installed on the computer.
OS	System returns the OS name. Windows XP and Windows 2000 display the OS as Windows_NT.
PATH	System specifies the search path for executable files.
PATHEXT	System returns a list of the file extensions that the OS considers to be executable.
PROCESSOR_ARCHITECTURE	System returns the processor's chip architecture. Values: x86, IA64, AMD64.
PROCESSOR_ARCHITEW6432	System returns the processor's chip architecture, if running a 32-bit application on Windows 64-bit. Values: IA64, AMD64.
PROCESSOR_IDENTFIER	System returns a description of the processor.
PROCESSOR_LEVEL	System returns the model number of the computer's processor.
PROCESSOR_REVISION	System returns the revision number of the processor.
PROGRAMFILES	Returns the location of the Program Files directory.
PROGRAMFILES(x86)	Returns the location of the Program Files directory for 32-bit applications on Windows 64-bit.
PROGRAMW6432	Returns the location of the Program Files directory for 64-bit applications on Windows 64-bit, if running a 32-bit application.
PROMPT	Local returns the command-prompt settings for the current interpreter. Cmd.exe generates this variable.
RANDOM	System returns a random decimal number between 0 and 32767. Cmd.exe generates this variable.
SYSTEMDRIVE	System returns the drive containing the Windows root directory (i.e., the system root).
SYSTEMROOT	System returns the location of the Windows root directory.
TEMP or TMP	System and User return the default temporary directories for applications that are available to users who are currently logged on. Some applications require TEMP and others require TMP.
TIME	System returns the current time. This variable uses the same format as the time /t command. Cmd.exe generates this variable. For more information about the time command, see the Time command.
USERDOMAIN	Local returns the name of the domain that contains the user's account.
USERNAME	Local returns the name of the user currently logged on.
USERPROFILE	Local returns the location of the profile for the current user.
WINDIR	System returns the location of the OS directory.