使用系统变量比使用绝对路径更安全（注意WinXP和后面的系统有不同之处）。
| Variable | Locale specific | Windows XP (CMD) | Windows Vista/7/8 (CMD) |
|---|---|---|---|
| %ALLUSERSPROFILE%[7] | Yes | C:\Documents and Settings\All Users | C:\ProgramData[7] |
| %APPDATA%[7] | Yes | C:\Documents and Settings\{username}\Application Data | C:\Users\{username}\AppData\Roaming[7] |
| %CommonProgramFiles%[7] | Yes | C:\Program Files\Common Files | C:\Program Files\Common Files[7] |
| %CommonProgramFiles(x86)%[7] | Yes | C:\Program Files (x86)\Common Files (only in 64-bit version) | C:\Program Files (x86)\Common Files (only in 64-bit version)[7] |
| %CommonProgramW6432%[7] | Yes | %CommonProgramW6432% (not supported, not replaced by any value) | C:\Program Files\Common Files (only in 64-bit version)[7] |
| %COMPUTERNAME% | No | {computername} | {computername} |
| %ComSpec% | No | C:\Windows\System32\cmd.exe | C:\Windows\System32\cmd.exe |
| %HOMEDRIVE%[7] | No | C: | C:[7] |
| %HOMEPATH%[7] | Yes | \Documents and Settings\{username} | \Users\{username}[7] |
| %LOCALAPPDATA%[7] | Yes | %LOCALAPPDATA% (not supported, not replaced by any value) | C:\Users\{username}\AppData\Local[7] |
| %LOGONSERVER% | No | \\{domain_logon_server} | \\{domain_logon_server} |
| %PATH% | Yes | C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;{plus program paths} | C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;{plus program paths} |
| %PATHEXT% | No | .COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.WSF;.WSH | .com;.exe;.bat;.cmd;.vbs;.vbe;.js;.jse;.wsf;.wsh;.msc |
| %ProgramData%[7] | Yes | %ProgramData% (not supported, not replaced by any value) | %SystemDrive%\ProgramData[7] |
| %ProgramFiles%[7] | Yes | %SystemDrive%\Program Files | %SystemDrive%\Program Files[7] |
| %ProgramFiles(x86)%[7] | Yes | %SystemDrive%\Program Files (x86) (only in 64-bit version) | %SystemDrive%\Program Files (x86) (only in 64-bit version)[7] |
| %ProgramW6432%[7] | Yes | %ProgramW6432% (not supported, not replaced by any value) | %SystemDrive%\Program Files (only in 64-bit version)[7] |
| %PROMPT% | No | Code for current command prompt format, usually $P$G | Code for current command prompt format, usually $P$G |
| %PSModulePath% | %PSModulePath% (not supported, not replaced by any value) | %SystemRoot%\system32\WindowsPowerShell\v1.0\Modules\ | |
| %PUBLIC%[7] | Yes | %PUBLIC% (not supported, not replaced by any value) | %SystemDrive%\Users\Public[7] |
| %SystemDrive%[7] | No | C: | C:[7] |
| %SystemRoot%[7] | No | The Windows directory, usually C:\Windows, formerly C:\WINNT | %SystemDrive%\Windows[7] |
| %TEMP%[7] and %TMP%[7] | Yes | %SystemDrive%\Documents and Settings\{username}\Local Settings\Temp | %SystemRoot%\TEMP (for system environment variables %TMP% and %TEMP%), %USERPROFILE%\AppData\Local\Temp\AppData\Local\Temp[7] (for user environment variables %TMP% and %TEMP%) |
| %USERDOMAIN% | No | {userdomain} | {userdomain} |
| %USERNAME% | No | {username} | {username} |
| %USERPROFILE%[7] | Yes | %SystemDrive%\Documents and Settings\{username} | %SystemDrive%\Users\{username}[7] |
| %windir%[7] | No | %SystemDrive%\WINDOWS | %SystemDrive%\Windows[7] |
https://en.wikipedia.org/wiki/Environment_variable
