环境变量保存在HKEY_LOCAL_MACHINE\SYSTEM\ControlSet\Control\Session Manager\Environment中。

许多有用的环境变量，如Path，都存储为REG_SZ。有几种方法可以访问注册表，包括REGEDIT:

REGEDIT /E <“HKEY_LOCAL_MACHINE \ SYSTEM \ ControlSet001 \会话管理器\ \控制环境”

输出从神奇的数字开始。因此，要用find命令搜索它，它需要输入并重定向:type <filename> | findstr -c:\"Path\"

所以，如果你只是想用系统属性刷新当前命令会话中的路径变量，下面的批处理脚本可以很好地工作:

RefreshPath.cmd:

    @echo off

    REM This solution requests elevation in order to read from the registry.

    if exist %temp%\env.reg del %temp%\env.reg /q /f

    REGEDIT /E %temp%\env.reg "HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Session Manager\Environment"

    if not exist %temp%\env.reg (
       echo "Unable to write registry to temp location"
       exit 1
       )

    SETLOCAL EnableDelayedExpansion

    for /f "tokens=1,2* delims==" %%i in ('type %temp%\env.reg ^| findstr -c:\"Path\"=') do (
       set upath=%%~j
       echo !upath:\\=\! >%temp%\newpath
       )

     ENDLOCAL

     for /f "tokens=*" %%i in (%temp%\newpath) do set path=%%i

使用“setx”并重新启动cmd提示符

有一个名为“setx”的命令行工具用于此作业。 它用于读取和写入env变量。 这些变量在命令窗口关闭后仍然存在。

创建或修改用户或系统环境中的环境变量，而不需要编程或脚本。setx命令还检索注册表项的值，并将它们写入文本文件。

注意:通过此工具创建或修改的变量将在以后的命令窗口中可用，但在当前CMD.exe命令窗口中不可用。所以，你必须重新开始。

如果缺少setx:

http://download.microsoft.com/download/win2000platform/setx/1.00.0.1/nt5/en-us/setx_setup.exe

或修改注册表

MSDN说:

若要以编程方式添加或修改系统环境变量，请使用add 他们去 HKEY_LOCAL_MACHINE \ System \ CurrentControlSet \ \控制会话 Manager\Environment注册表项，然后广播一个WM_SETTINGCHANGE 消息，lParam设置为字符串“环境”。 这允许应用程序(如shell)接收您的更新。

更有可能的是，您希望已打开和/或正在运行的应用程序可以访问更新的环境变量。因此，最好和最简单的操作方法是关闭/重新打开应用程序，以便它接收更新后的环境变量。

幕后的细节是非常微妙的，但是上面的内容应该适用于大多数用例。

我已经用了几年的解决方案:

@echo off
rem Refresh PATH from registry.
setlocal
set USR_PATH=
set SYS_PATH=
for /F "tokens=3* skip=2" %%P in ('%SystemRoot%\system32\reg.exe query "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Environment" /v PATH') do @set "SYS_PATH=%%P %%Q"
for /F "tokens=3* skip=2" %%P in ('%SystemRoot%\system32\reg.exe query "HKCU\Environment" /v PATH') do @set "USR_PATH=%%P %%Q"
if "%SYS_PATH:~-1%"==" " set "SYS_PATH=%SYS_PATH:~0,-1%"
if "%USR_PATH:~-1%"==" " set "USR_PATH=%USR_PATH:~0,-1%"
endlocal & call set "PATH=%SYS_PATH%;%USR_PATH%"
goto :EOF

编辑:糟糕，这是更新版。

调用这个函数对我来说很有用:

VOID Win32ForceSettingsChange()
{
    DWORD dwReturnValue;
    ::SendMessageTimeout(HWND_BROADCAST, WM_SETTINGCHANGE, 0, (LPARAM) "Environment", SMTO_ABORTIFHUNG, 5000, &dwReturnValue);
}

我喜欢巧克力之后的方法，就像匿名懦夫的回答，因为这是一个纯粹的批量处理方法。但是，它会留下一个临时文件和一些临时变量。我给自己做了一个更干净的版本。

在路径的某个地方创建一个文件refreshv .bat。通过执行refreshEnv来刷新控制台环境。

@ECHO OFF
REM Source found on https://github.com/DieterDePaepe/windows-scripts
REM Please share any improvements made!

REM Code inspired by http://stackoverflow.com/questions/171588/is-there-a-command-to-refresh-environment-variables-from-the-command-prompt-in-w

IF [%1]==[/?] GOTO :help
IF [%1]==[/help] GOTO :help
IF [%1]==[--help] GOTO :help
IF [%1]==[] GOTO :main

ECHO Unknown command: %1
EXIT /b 1 

:help
ECHO Refresh the environment variables in the console.
ECHO.
ECHO   refreshEnv       Refresh all environment variables.
ECHO   refreshEnv /?        Display this help.
GOTO :EOF

:main
REM Because the environment variables may refer to other variables, we need a 2-step approach.
REM One option is to use delayed variable evaluation, but this forces use of SETLOCAL and
REM may pose problems for files with an '!' in the name.
REM The option used here is to create a temporary batch file that will define all the variables.

REM Check to make sure we don't overwrite an actual file.
IF EXIST %TEMP%\__refreshEnvironment.bat (
  ECHO Environment refresh failed!
  ECHO.
  ECHO This script uses a temporary file "%TEMP%\__refreshEnvironment.bat", which already exists. The script was aborted in order to prevent accidental data loss. Delete this file to enable this script.
  EXIT /b 1
)

REM Read the system environment variables from the registry.
FOR /F "usebackq tokens=1,2,* skip=2" %%I IN (`REG QUERY "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Environment"`) DO (
  REM /I -> ignore casing, since PATH may also be called Path
  IF /I NOT [%%I]==[PATH] (
    ECHO SET %%I=%%K>>%TEMP%\__refreshEnvironment.bat
  )
)

REM Read the user environment variables from the registry.
FOR /F "usebackq tokens=1,2,* skip=2" %%I IN (`REG QUERY HKCU\Environment`) DO (
  REM /I -> ignore casing, since PATH may also be called Path
  IF /I NOT [%%I]==[PATH] (
    ECHO SET %%I=%%K>>%TEMP%\__refreshEnvironment.bat
  )
)

REM PATH is a special variable: it is automatically merged based on the values in the
REM system and user variables.
REM Read the PATH variable from the system and user environment variables.
FOR /F "usebackq tokens=1,2,* skip=2" %%I IN (`REG QUERY "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Environment" /v PATH`) DO (
  ECHO SET PATH=%%K>>%TEMP%\__refreshEnvironment.bat
)
FOR /F "usebackq tokens=1,2,* skip=2" %%I IN (`REG QUERY HKCU\Environment /v PATH`) DO (
  ECHO SET PATH=%%PATH%%;%%K>>%TEMP%\__refreshEnvironment.bat
)

REM Load the variable definitions from our temporary file.
CALL %TEMP%\__refreshEnvironment.bat

REM Clean up after ourselves.
DEL /Q %TEMP%\__refreshEnvironment.bat

ECHO Environment successfully refreshed.