Environment variables are used in every Operating System, they are variables that you can call through the command prompt, a batch file or even through the Address Bar. Here is one of Microsoft’s definitions:
Environment variables are strings that contain information such as drive, path, or file name. They control the behavior of various programs. For example, the TEMP environment variable specifies the location in which programs place temporary files.
There are two categories of Environmental Variables, Local and System:
Local variables are set when the user logs in and will only pertain to that user, ie%APPDATA%
System variables pertain to Windows itself, ie %SYSTEMROOT%
Environment variables are strings that contain information such as drive, path, or file name. They control the behavior of various programs. For example, the TEMP environment variable specifies the location in which programs place temporary files.
There are two categories of Environmental Variables, Local and System:
Local variables are set when the user logs in and will only pertain to that user, ie%APPDATA%
System variables pertain to Windows itself, ie %SYSTEMROOT%
Note
I wrote the list in uppercase, but these variables are not case sensitive when you actually call them! Remember that you will need to include the percent signs when calling these variables, ie:
C:\Documents and Settings\%username%\Application Data
I wrote the list in uppercase, but these variables are not case sensitive when you actually call them! Remember that you will need to include the percent signs when calling these variables, ie:
C:\Documents and Settings\%username%\Application Data
Also, you can invoke most of these variables through the handy Windows Run prompt. Just hit the Windows Key+R, then enter the command and the system will open that folder!
The List
The list is in alphabetic order
%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.
%DATE% – System
Returns the current date. Uses the same format as the date /t command. Generated by Cmd.exe.
%ERRORLEVEL% – System
Returns the error code of the most recently used command. A non zero value usually indicates an error.
%HOMEDRIVE% – System
Returns which local workstation drive letter is connected to the user’s home directory. 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. 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. 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 operating system name. Windows 2000 displays the operating system as Windows_NT.
%PATH% – System
Specifies the search path for executable files.
%PATHEXT% – System
Returns a list of the file extensions that the operating system considers to be executable.
%PROCESSOR_ARCHITECTURE% – System
Returns the chip architecture of the processor. Values: x86, IA64.
%PROCESSOR_IDENTIFIER% – System
Returns a description of the processor.
%PROCESSOR_LEVEL% – System
Returns the model number of the processor installed on the computer.
%PROCESSOR_REVISION% – System
Returns the revision number of the processor.
%PROMPT% – Local
Returns the command prompt settings for the current interpreter. Generated by Cmd.exe.
%RANDOM% – System
Returns a random decimal number between 0 and 32767. Generated by Cmd.exe.
%SYSTEMDRIVE% – System
Returns the drive containing the Windows XP root directory (that is, the system root).
%SYSTEMROOT% – System
Returns the location of the Windows XP root directory.
%TEMP% and %TMP% – System and User
Returns the default temporary directories that are used by applications available to users who are currently logged on. Some applications require TEMP and others require TMP.
%TIME% – System
Returns the current time. Uses the same format as the time /t command. Generated by Cmd.exe.
%USERDOMAIN% – Local
Returns the name of the domain that contains the user’s account.
%USERNAME% – Local
Returns the name of the user who is currently logged on.
%USERPROFILE% – Local
Returns the location of the profile for the current user.
%WINDIR% – System
Returns the location of the operating system directory.
The List
The list is in alphabetic order
%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.
%DATE% – System
Returns the current date. Uses the same format as the date /t command. Generated by Cmd.exe.
%ERRORLEVEL% – System
Returns the error code of the most recently used command. A non zero value usually indicates an error.
%HOMEDRIVE% – System
Returns which local workstation drive letter is connected to the user’s home directory. 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. 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. 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 operating system name. Windows 2000 displays the operating system as Windows_NT.
%PATH% – System
Specifies the search path for executable files.
%PATHEXT% – System
Returns a list of the file extensions that the operating system considers to be executable.
%PROCESSOR_ARCHITECTURE% – System
Returns the chip architecture of the processor. Values: x86, IA64.
%PROCESSOR_IDENTIFIER% – System
Returns a description of the processor.
%PROCESSOR_LEVEL% – System
Returns the model number of the processor installed on the computer.
%PROCESSOR_REVISION% – System
Returns the revision number of the processor.
%PROMPT% – Local
Returns the command prompt settings for the current interpreter. Generated by Cmd.exe.
%RANDOM% – System
Returns a random decimal number between 0 and 32767. Generated by Cmd.exe.
%SYSTEMDRIVE% – System
Returns the drive containing the Windows XP root directory (that is, the system root).
%SYSTEMROOT% – System
Returns the location of the Windows XP root directory.
%TEMP% and %TMP% – System and User
Returns the default temporary directories that are used by applications available to users who are currently logged on. Some applications require TEMP and others require TMP.
%TIME% – System
Returns the current time. Uses the same format as the time /t command. Generated by Cmd.exe.
%USERDOMAIN% – Local
Returns the name of the domain that contains the user’s account.
%USERNAME% – Local
Returns the name of the user who is currently logged on.
%USERPROFILE% – Local
Returns the location of the profile for the current user.
%WINDIR% – System
Returns the location of the operating system directory.
