如果修改或添加环境变量，则必须重新启动命令提示符。是否有一个命令，我可以执行，将这样做而不重新启动CMD?
当前回答
以下是Chocolatey使用的方法。
https://github.com/chocolatey/choco/blob/master/src/chocolatey.resources/redirects/RefreshEnv.cmd
@echo off
::
:: RefreshEnv.cmd
::
:: Batch file to read environment variables from registry and
:: set session variables to these values.
::
:: With this batch file, there should be no need to reload command
:: environment every time you want environment changes to propagate
::echo "RefreshEnv.cmd only works from cmd.exe, please install the Chocolatey Profile to take advantage of refreshenv from PowerShell"
echo | set /p dummy="Refreshing environment variables from registry for cmd.exe. Please wait..."
goto main
:: Set one environment variable from registry key
:SetFromReg
"%WinDir%\System32\Reg" QUERY "%~1" /v "%~2" > "%TEMP%\_envset.tmp" 2>NUL
for /f "usebackq skip=2 tokens=2,*" %%A IN ("%TEMP%\_envset.tmp") do (
echo/set "%~3=%%B"
)
goto :EOF
:: Get a list of environment variables from registry
:GetRegEnv
"%WinDir%\System32\Reg" QUERY "%~1" > "%TEMP%\_envget.tmp"
for /f "usebackq skip=2" %%A IN ("%TEMP%\_envget.tmp") do (
if /I not "%%~A"=="Path" (
call :SetFromReg "%~1" "%%~A" "%%~A"
)
)
goto :EOF
:main
echo/@echo off >"%TEMP%\_env.cmd"
:: Slowly generating final file
call :GetRegEnv "HKLM\System\CurrentControlSet\Control\Session Manager\Environment" >> "%TEMP%\_env.cmd"
call :GetRegEnv "HKCU\Environment">>"%TEMP%\_env.cmd" >> "%TEMP%\_env.cmd"
:: Special handling for PATH - mix both User and System
call :SetFromReg "HKLM\System\CurrentControlSet\Control\Session Manager\Environment" Path Path_HKLM >> "%TEMP%\_env.cmd"
call :SetFromReg "HKCU\Environment" Path Path_HKCU >> "%TEMP%\_env.cmd"
:: Caution: do not insert space-chars before >> redirection sign
echo/set "Path=%%Path_HKLM%%;%%Path_HKCU%%" >> "%TEMP%\_env.cmd"
:: Cleanup
del /f /q "%TEMP%\_envset.tmp" 2>nul
del /f /q "%TEMP%\_envget.tmp" 2>nul
:: capture user / architecture
SET "OriginalUserName=%USERNAME%"
SET "OriginalArchitecture=%PROCESSOR_ARCHITECTURE%"
:: Set these variables
call "%TEMP%\_env.cmd"
:: Cleanup
del /f /q "%TEMP%\_env.cmd" 2>nul
:: reset user / architecture
SET "USERNAME=%OriginalUserName%"
SET "PROCESSOR_ARCHITECTURE=%OriginalArchitecture%"
echo | set /p dummy="Finished."
echo .
其他回答
令人困惑的事情可能是，有几个地方可以启动cmd。 在我的情况下，我从windows资源管理器运行cmd，环境变量没有改变，而当从“运行”(windows键+ r)开始cmd时，环境变量被改变了。
在我的情况下，我只需要从任务管理器中杀死windows资源管理器进程，然后从任务管理器中重新启动它。
一旦我这样做了，我就可以从windows资源管理器衍生的cmd中访问新的环境变量。
如果它只涉及一个(或几个)特定的变量，你想要改变，我认为最简单的方法是一个变通方法:在你的环境和当前的控制台会话中设置
Set将把变量放在当前会话中 SetX将把变量放在环境中，但不是在当前会话中
我使用这个简单的批处理脚本将Maven从Java7更改为Java8(两者都是env。批处理文件夹在我的PATH变量中，所以我总是可以调用'j8'，在我的控制台和环境中，我的JAVA_HOME变量被改变:
j8.bat:
@echo off
set JAVA_HOME=%JAVA_HOME_8%
setx JAVA_HOME "%JAVA_HOME_8%"
到目前为止，我发现这是最好的和最简单的工作。 你可能希望这是在一个命令中，但它只是没有在Windows…
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.
我使用这个Powershell脚本添加到PATH变量中。 只要稍加调整，我相信它也适用于你的情况。
#REQUIRES -Version 3.0
if (-not ("win32.nativemethods" -as [type])) {
# import sendmessagetimeout from win32
add-type -Namespace Win32 -Name NativeMethods -MemberDefinition @"
[DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
public static extern IntPtr SendMessageTimeout(
IntPtr hWnd, uint Msg, UIntPtr wParam, string lParam,
uint fuFlags, uint uTimeout, out UIntPtr lpdwResult);
"@
}
$HWND_BROADCAST = [intptr]0xffff;
$WM_SETTINGCHANGE = 0x1a;
$result = [uintptr]::zero
function global:ADD-PATH
{
[Cmdletbinding()]
param (
[parameter(Mandatory=$True, ValueFromPipeline=$True, Position=0)]
[string] $Folder
)
# See if a folder variable has been supplied.
if (!$Folder -or $Folder -eq "" -or $Folder -eq $null) {
throw 'No Folder Supplied. $ENV:PATH Unchanged'
}
# Get the current search path from the environment keys in the registry.
$oldPath=$(Get-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Environment' -Name PATH).Path
# See if the new Folder is already in the path.
if ($oldPath | Select-String -SimpleMatch $Folder){
return 'Folder already within $ENV:PATH'
}
# Set the New Path and add the ; in front
$newPath=$oldPath+';'+$Folder
Set-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Environment' -Name PATH -Value $newPath -ErrorAction Stop
# Show our results back to the world
return 'This is the new PATH content: '+$newPath
# notify all windows of environment block change
[win32.nativemethods]::SendMessageTimeout($HWND_BROADCAST, $WM_SETTINGCHANGE, [uintptr]::Zero, "Environment", 2, 5000, [ref]$result)
}
function global:REMOVE-PATH {
[Cmdletbinding()]
param (
[parameter(Mandatory=$True, ValueFromPipeline=$True, Position=0)]
[String] $Folder
)
# See if a folder variable has been supplied.
if (!$Folder -or $Folder -eq "" -or $Folder -eq $NULL) {
throw 'No Folder Supplied. $ENV:PATH Unchanged'
}
# add a leading ";" if missing
if ($Folder[0] -ne ";") {
$Folder = ";" + $Folder;
}
# Get the Current Search Path from the environment keys in the registry
$newPath=$(Get-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Environment' -Name PATH).Path
# Find the value to remove, replace it with $NULL. If it's not found, nothing will change and you get a message.
if ($newPath -match [regex]::Escape($Folder)) {
$newPath=$newPath -replace [regex]::Escape($Folder),$NULL
} else {
return "The folder you mentioned does not exist in the PATH environment"
}
# Update the Environment Path
Set-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Environment' -Name PATH -Value $newPath -ErrorAction Stop
# Show what we just did
return 'This is the new PATH content: '+$newPath
# notify all windows of environment block change
[win32.nativemethods]::SendMessageTimeout($HWND_BROADCAST, $WM_SETTINGCHANGE, [uintptr]::Zero, "Environment", 2, 5000, [ref]$result)
}
# Use ADD-PATH or REMOVE-PATH accordingly.
#Anything to Add?
#Anything to Remove?
REMOVE-PATH "%_installpath_bin%"
谢谢你提出这个非常有趣的问题，即使在2019年(事实上，更新shell cmd并不容易，因为如上所述，它是一个单一的实例)，因为在windows中更新环境变量允许完成许多自动化任务，而无需手动重新启动命令行。
例如，我们使用它来允许在我们定期重新安装的大量机器上部署和配置软件。我必须承认，在软件部署期间重新启动命令行是非常不切实际的，而且需要我们找到不一定令人愉快的变通办法。 让我们来解决问题。 我们按以下步骤进行。
1 -我们有一个批处理脚本，它依次调用powershell脚本
(文件:task.cmd)。
cmd > powershell.exe -executionpolicy unlimited -File C:\path_here\refresh.ps1 .exe
2 -在此之后，刷新。ps1脚本使用注册表键(GetValueNames()等)更新环境变量。 然后，在同一个powershell脚本中，我们只需要调用新的环境变量即可。 例如，在一个典型的情况下，如果我们之前刚刚用静默命令用cmd安装了nodeJS，在函数被调用后，我们可以直接调用npm来安装，在同一个会话中，如下所示的特定包。
(文件:refresh.ps1)
function Update-Environment {
$locations = 'HKLM:\SYSTEM\CurrentControlSet\Control\Session Manager\Environment',
'HKCU:\Environment'
$locations | ForEach-Object {
$k = Get-Item $_
$k.GetValueNames() | ForEach-Object {
$name = $_
$value = $k.GetValue($_)
if ($userLocation -and $name -ieq 'PATH') {
$env:Path += ";$value"
} else {
Set-Item -Path Env:\$name -Value $value
}
}
$userLocation = $true
}
}
Update-Environment
#Here we can use newly added environment variables like for example npm install..
npm install -g create-react-app serve
powershell脚本结束后，cmd脚本继续执行其他任务。 现在，要记住的一件事是，在任务完成后，cmd仍然不能访问新的环境变量，即使powershell脚本在它自己的会话中更新了这些变量。这就是为什么我们在powershell脚本中完成所有需要的任务，它当然可以调用与cmd相同的命令。
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