根据设计，Windows没有内置机制来将环境变量添加/更改/删除传播到已经运行的cmd.exe中，无论是从另一个cmd.exe还是从“我的电脑->属性->高级设置->环境变量”。

如果在现有的开放命令提示符范围之外修改或添加新的环境变量，则需要重新启动命令提示符，或者在现有的命令提示符中使用SET手动添加。

最新接受的答案通过手动刷新脚本中的所有环境变量显示了部分解决方案。该脚本处理在“My Computer…”中全局更改环境变量的用例。但是如果一个环境变量在一个cmd.exe中被更改，脚本不会将其传播到另一个运行cmd.exe的环境变量中。

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。

我想到的最好的方法是只做一个Registry查询。下面是我的例子。

In my example I did an install using a Batch file that added new environment variables. I needed to do things with this as soon as the install was complete, but was unable to spawn a new process with those new variables. I tested spawning another explorer window and called back to cmd.exe and this worked but on Vista and Windows 7, Explorer only runs as a single instance and normally as the person logged in. This would fail with automation since I need my admin creds to do things regardless of running from local system or as an administrator on the box. The limitation to this is that it does not handle things like path, this only worked on simple enviroment variables. This allowed me to use a batch to get over to a directory (with spaces) and copy in files run .exes and etc. This was written today from may resources on stackoverflow.com

原批处理调用新批处理:

testenvget。cmd SDROOT(或任何变量)

@ECHO OFF
setlocal ENABLEEXTENSIONS
set keyname=HKLM\System\CurrentControlSet\Control\Session Manager\Environment
set value=%1
SET ERRKEY=0

REG QUERY "%KEYNAME%" /v "%VALUE%" 2>NUL| FIND /I "%VALUE%"
IF %ERRORLEVEL% EQU 0 (
ECHO The Registry Key Exists 
) ELSE (
SET ERRKEY=1
Echo The Registry Key Does not Exist
)

Echo %ERRKEY%
IF %ERRKEY% EQU 1 GOTO :ERROR

FOR /F "tokens=1-7" %%A IN ('REG QUERY "%KEYNAME%" /v "%VALUE%" 2^>NUL^| FIND /I "%VALUE%"') DO (
ECHO %%A
ECHO %%B
ECHO %%C
ECHO %%D
ECHO %%E
ECHO %%F
ECHO %%G
SET ValueName=%%A
SET ValueType=%%B
SET C1=%%C
SET C2=%%D
SET C3=%%E
SET C4=%%F
SET C5=%%G
)

SET VALUE1=%C1% %C2% %C3% %C4% %C5%
echo The Value of %VALUE% is %C1% %C2% %C3% %C4% %C5%
cd /d "%VALUE1%"
pause
REM **RUN Extra Commands here**
GOTO :EOF

:ERROR
Echo The the Enviroment Variable does not exist.
pause
GOTO :EOF

还有另一种方法，我从各种不同的想法中想出的。请看下文。这基本上会得到最新的路径变量从注册表然而，这将导致一些问题，因为注册表查询将给出变量本身，这意味着到处都有一个变量，这将不会工作，所以为了解决这个问题，我基本上加倍的路径。非常讨厌的。更可取的方法是: 设置路径=%路径%;C:\Program Files\Software....\

不管这是新的批处理文件，请谨慎使用。

@ECHO OFF
SETLOCAL ENABLEEXTENSIONS
set org=%PATH%
for /f "tokens=2*" %%A in ('REG QUERY "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Environment" /v Path ^|FIND /I "Path"') DO (
SET path=%%B
)
SET PATH=%org%;%PATH%
set path

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。

可以通过在指定进程本身中覆盖环境表来实现这一点。

作为概念的证明，我写了这个示例应用程序，它只是在cmd.exe进程中编辑一个(已知的)环境变量:

typedef DWORD (__stdcall *NtQueryInformationProcessPtr)(HANDLE, DWORD, PVOID, ULONG, PULONG);

int __cdecl main(int argc, char* argv[])
{
    HMODULE hNtDll = GetModuleHandleA("ntdll.dll");
    NtQueryInformationProcessPtr NtQueryInformationProcess = (NtQueryInformationProcessPtr)GetProcAddress(hNtDll, "NtQueryInformationProcess");

    int processId = atoi(argv[1]);
    printf("Target PID: %u\n", processId);

    // open the process with read+write access
    HANDLE hProcess = OpenProcess(PROCESS_QUERY_LIMITED_INFORMATION | PROCESS_VM_READ | PROCESS_VM_WRITE | PROCESS_VM_OPERATION, 0, processId);
    if(hProcess == NULL)
    {
        printf("Error opening process (%u)\n", GetLastError());
        return 0;
    }

    // find the location of the PEB
    PROCESS_BASIC_INFORMATION pbi = {0};
    NTSTATUS status = NtQueryInformationProcess(hProcess, ProcessBasicInformation, &pbi, sizeof(pbi), NULL);
    if(status != 0)
    {
        printf("Error ProcessBasicInformation (0x%8X)\n", status);
    }
    printf("PEB: %p\n", pbi.PebBaseAddress);

    // find the process parameters
    char *processParamsOffset = (char*)pbi.PebBaseAddress + 0x20; // hard coded offset for x64 apps
    char *processParameters = NULL;
    if(ReadProcessMemory(hProcess, processParamsOffset, &processParameters, sizeof(processParameters), NULL))
    {
        printf("UserProcessParameters: %p\n", processParameters);
    }
    else
    {
        printf("Error ReadProcessMemory (%u)\n", GetLastError());
    }

    // find the address to the environment table
    char *environmentOffset = processParameters + 0x80; // hard coded offset for x64 apps
    char *environment = NULL;
    ReadProcessMemory(hProcess, environmentOffset, &environment, sizeof(environment), NULL);
    printf("environment: %p\n", environment);

    // copy the environment table into our own memory for scanning
    wchar_t *localEnvBlock = new wchar_t[64*1024];
    ReadProcessMemory(hProcess, environment, localEnvBlock, sizeof(wchar_t)*64*1024, NULL);

    // find the variable to edit
    wchar_t *found = NULL;
    wchar_t *varOffset = localEnvBlock;
    while(varOffset < localEnvBlock + 64*1024)
    {
        if(varOffset[0] == '\0')
        {
            // we reached the end
            break;
        }
        if(wcsncmp(varOffset, L"ENVTEST=", 8) == 0)
        {
            found = varOffset;
            break;
        }
        varOffset += wcslen(varOffset)+1;
    }

    // check to see if we found one
    if(found)
    {
        size_t offset = (found - localEnvBlock) * sizeof(wchar_t);
        printf("Offset: %Iu\n", offset);

        // write a new version (if the size of the value changes then we have to rewrite the entire block)
        if(!WriteProcessMemory(hProcess, environment + offset, L"ENVTEST=def", 12*sizeof(wchar_t), NULL))
        {
            printf("Error WriteProcessMemory (%u)\n", GetLastError());
        }
    }

    // cleanup
    delete[] localEnvBlock;
    CloseHandle(hProcess);

    return 0;
}

样例输出:

>set ENVTEST=abc

>cppTest.exe 13796
Target PID: 13796
PEB: 000007FFFFFD3000
UserProcessParameters: 00000000004B2F30
environment: 000000000052E700
Offset: 1528

>set ENVTEST
ENVTEST=def

笔记

这种方法也仅限于安全限制。如果目标在更高的海拔或更高的帐户(如SYSTEM)上运行，那么我们将没有权限编辑它的内存。

如果你想对一个32位的应用程序这样做，上面的硬编码偏移量将分别更改为0x10和0x48。这些偏移量可以通过在调试器中转储_PEB和_RTL_USER_PROCESS_PARAMETERS结构体来找到(例如在WinDbg dt _PEB和dt _RTL_USER_PROCESS_PARAMETERS中)

要将概念证明更改为OP需要的内容，只需枚举当前系统和用户环境变量(如@tsadok的答案所记录的那样)，并将整个环境表写入目标进程的内存中。

Edit: The size of the environment block is also stored in the _RTL_USER_PROCESS_PARAMETERS struct, but the memory is allocated on the process' heap. So from an external process we wouldn't have the ability to resize it and make it larger. I played around with using VirtualAllocEx to allocate additional memory in the target process for the environment storage, and was able to set and read an entirely new table. Unfortunately any attempt to modify the environment from normal means will crash and burn as the address no longer points to the heap (it will crash in RtlSizeHeap).

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 .