Common XP environment variables[转 ]

Common XP environment variables

ALLUSERSPROFILE      location of the All Users Profile.
APPDATA              location where applications store data by default.
CD                   current directory string.
CLIENTNAME           client's NETBIOS name when connected to terminal server session.
CMDCMDLINE           command line used to start the current cmd.exe.
CMDEXTVERSION        version number of the current Command Processor Extensions.
CommonProgramFiles   path to the Common Files folder.
COMPUTERNAME         name of the computer.
COMSPEC              path to the command shell executable.
DATE                 current date.
ERRORLEVEL           error code of the most recently used command.
HOMEDRIVE            drive letter is connected to the user's home directory.
HOMEPATH             full path of the user's home directory.
HOMESHARE            network path to the user's shared home directory.
LOGONSEVER           name of the domain controller that validated the current logon session.
NUMBER_OF_PROCESSORS   number of processors installed on the computer.
OS                   name of the operating system. 
                     (Windows XP and Windows 2000 list the operating system as Windows_NT.)
Path                 search path for executable files.
PATHEXT              file extensions that the operating system considers to be executable.
PROCESSOR_ARCHITECTURE   processor's chip architecture.
PROCESSOR_IDENTFIER  description of the processor.
PROCESSOR_LEVEL      model number of the computer's processor.
PROCESSOR_REVISION   revision number of the processor.
ProgramFiles         path to the Program Files folder.
PROMPT               command-prompt settings for the current interpreter.
RANDOM               random decimal number between 0 and 32767.
SESSIONNAME          connection and session names when connected to terminal server session.
SYSTEMDRIVE          drive containing the Windows root directory.
SYSTEMROOT           location of the Windows root directory.
TEMP and TMP         default temporary directories for applications that are available to 
                     users who are currently logged on.
TIME                 current time.
USERDOMAIN           name of the domain that contains the user's account.
USERNAME             name of the user currently logged on.
USERPROFILE          location of the profile for the current user.
WINDIR               location of the OS directory.

To read an environment variable, see these HowTo's for Powerbuilder , Java and VBScript .