在 Windows 操作系统下工作，免不了用上几次 cmd，收集一些必要的系统内置环境变量。
| Variable | Volatile (Read-Only) |
Default value in Windows (system drive is C: ) |
|---|---|---|
| ALLUSERSPROFILE | C:\ProgramData |
|
| APPDATA | C:\Users\{username}\AppData\Roaming |
|
| CD | Y | The current directory (string). |
| ClientName | Y | Terminal servers only - the ComputerName of a remote host. |
| CMDEXTVERSION | Y | The current Command Processor Extensions version number. (NT = “1”, Win2000+ = “2”.) |
| CMDCMDLINE | Y | The original command line that invoked the Command Processor. |
| CommonProgramFiles | C:\Program Files\Common Files |
|
| COMMONPROGRAMFILES(x86) | C:\Program Files (x86)\Common Files |
|
| COMPUTERNAME | {computername} |
|
| COMSPEC | C:\Windows\System32\cmd.exe or if running a 32 bit WOW - C:\Windows\SysWOW64\cmd.exe |
|
| DATE | Y | The current date using same region specific format as DATE. |
| ERRORLEVEL | Y | The current ERRORLEVEL value, automatically set when a program exits. |
| FPS_BROWSER_APP_PROFILE_STRING FPS_BROWSER_USER_PROFILE_STRING |
Internet Explorer Default These are undocumented variables for the Edge browser in Windows 10. |
|
| HighestNumaNodeNumber | Y (hidden) | The highest NUMA node number on this computer. |
| HOMEDRIVE | Y | C: |
| HOMEPATH | Y | \Users\{username} |
| LOCALAPPDATA | C:\Users\{username}\AppData\Local |
|
| LOGONSERVER | \\{domain_logon_server} |
|
| NUMBER_OF_PROCESSORS | Y | The Number of processors running on the machine. |
| OS | Y | Operating system on the user’s workstation. |
| PATH | User and System | C:\Windows\System32\;C:\Windows\;C:\Windows\System32\Wbem;{plus program paths} |
| PATHEXT | .COM; .EXE; .BAT; .CMD; .VBS; .VBE; .JS ; .WSF; .WSH; .MSC The syntax is like the PATH variable - semicolon separators. |
|
| PROCESSOR_ARCHITECTURE | Y | AMD64/IA64/x86 This doesn’t tell you the architecture of the processor but only of the current process, so it returns “x86” for a 32 bit WOW process running on 64 bit Windows. See detecting OS 32/64 bit |
| PROCESSOR_ARCHITEW6432 | =%ProgramFiles% (only available on 64 bit systems) |
|
| PROCESSOR_IDENTIFIER | Y | Processor ID of the user’s workstation. |
| PROCESSOR_LEVEL | Y | Processor level of the user’s workstation. |
| PROCESSOR_REVISION | Y | Processor version of the user’s workstation. |
| ProgramW6432 | =%PROCESSOR_ARCHITECTURE% (only available on 64 bit systems) |
|
| ProgramData | C:\ProgramData |
|
| ProgramFiles | C:\Program Files or C:\Program Files (x86) |
|
| ProgramFiles(x86) | C:\Program Files (x86) |
|
| PROMPT | Code for current command prompt format,usually $P$G C:> |
|
| PSModulePath | %SystemRoot%\system32\WindowsPowerShell\v1.0\Modules\ |
|
| Public | C:\Users\Public |
|
| RANDOM | Y | A random integer number, anything from 0 to 32,767 (inclusive). |
| %SessionName% | Terminal servers only - for a terminal server session, SessionName is a combination of the connection name, followed by #SessionNumber. For a console session, SessionName returns “Console”. | |
| SYSTEMDRIVE | C: By default, Windows is installed to C:\Windows but there’s no guarantee of that, Windows can be installed to a different folder, or a different drive letter. systemroot is a read-only system variable that will resolve to the correct location. NT 4.0, Windows 2000 and Windows NT 3.1 default to C:\WINNT |
|
| TEMP and TMP | User Variable | C:\Users\{Username}\AppData\Local\Temp Under XP this was \{username}\Local Settings\Temp |
| TIME | Y | The current time using same format as TIME. |
| UserDnsDomain | Y User Variable |
Set if a user is a logged on to a domain and returns the fully qualified DNS domain that the currently logged on user’s account belongs to. |
| USERDOMAIN | {userdomain} |
|
| USERDOMAIN_roamingprofile | The user domain for RDS or standard roaming profile paths. Windows 8/10/2012 (or Windows 7/2008 with Q2664408) | |
| USERNAME | {username} |
|
| USERPROFILE | %SystemDrive%\Users\{username} This is equivalent to the $HOME environment variable in Unix/Linux |
|
| WINDIR | %WinDir% pre-dates Windows NT and seems to be superseded by %SystemRoot% Set by default as windir=%SystemRoot% %windir% is a regular variable and can be changed, which makes it less robust than %systemroot% |