Environment Variables in Windows Vista and Windows 7

原文: http://www.vlaurie.com/computers2/Articles/environment-variables-windows-vista-7.htm

 

 

The discussion of environment variables in Windows begun in the previous article is continued. Here we look at the environment variables for Windows Vista and Windows 7.Environment variables for Windows Vista and Windows 7

Much of the discussion given in the article on Windows XP environment variables is applcable to Windows Vista and Windows 7. However, there are some differences and some new variables and we will look at what has changed. The table below shows common preset environment variables in the two operating systems. Changes from Windows XP are noted in red. More technical terms about things like the processor architecture are omitted.

 

 

Table I. Some more common predefined environment variables in Windows Vista and 7

Variable	Typical value (May vary, depending on system)
%ALLUSERSPROFILE%	C:\ProgramData
%APPDATA%	C:\Users\(username}\AppData\Roaming
%CommonProgramFiles%	C:\Program Files\Common Files
%COMPUTERNAME%	{computername}
%COMSPEC%	C:\Windows\System32\cmd.exe
%HOMEDRIVE%	C:
%HOMEPATH%	\Users\{username}
%LOCALAPPDATA%	C:\Users\{username}\AppData\Local
%PATH%	Varies. Includes C:\Windows\System32\;C:\Windows\;C:\Windows\System32\Wbem
%PATHEXT%	.COM; .EXE; .BAT; .CMD; .VBS; .VBE; .JS ; .WSF; .WSH; .MSC
%ProgramData%	C:\ProgramData
%PROGRAMFILES%	Directory containing program files, usually C:\Program Files
%ProgramFiles(x86)%	In 64-bit systems, directory containing 32-bit programs. Usually C:\Program Files (x86)
%PROMPT%	Code for current command prompt format. Code is usually $P$G
%Public%	C:\Users\Public
%SYSTEMDRIVE%	The drive containing the Windows XP root directory, usually C:
%SYSTEMROOT%	The Windows XP root directory, usually C:\Windows
%TEMP% and %TMP%	C:\Users\{Username}\AppData\Local\Temp
%USERNAME%	{username}
%USERPROFILE%	C:\Users\{username}
%WINDIR%	C:\Windows

Note the changes from Windows XP for the locations of many of the personal files and settings. For example, the "Documents and Settings" folder is gone and there is now a "Users" folder. There are also four new environment variables listed in Table I. These are:
%CommonProgramFiles%
%LocalAppdata%
%ProgramData%
%Public%

The common dynamic variables are the same as given for XP

Changes in environment variables between Vista and Windows 7

There are few changes in the common variables in going from Windows Vista to Windows 7. As far as I can tell, there is only one worth mentioning. Windows 7 comes with the newer Microsoft command line shell called Powershell. There is an environment varaiable %PSModulePath% that gives the path to the files for the command line shell. This is usually C:\windows\system32\WindowsPowerShell\v1.0\Modules\

List environment variables in Windows 7 using PowerShell

In the classical command line, environment variables can be listed with the "set" command. Beginning with Windows7, Microsoft began including the newer command shell called "PowerShell". The command for listing environment variables in this newer shell is Get-ChildItem Env: