cmd environment variable not updated code example

Example: cmd refresh path

# Add these lines to a batch file, which
# you can then call to refresh the path
# variable of your current session:

@echo off
echo | set /p dummy="Reading environment variables from registry. Please wait... "
goto main
: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
: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"
    call :GetRegEnv "HKLM\System\CurrentControlSet\Control\Session Manager\Environment" >> "%TEMP%\_env.cmd"
    call :GetRegEnv "HKCU\Environment">>"%TEMP%\_env.cmd" >> "%TEMP%\_env.cmd"
    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"
    echo/set Path=%%Path_HKLM%%;%%Path_HKCU%% >> "%TEMP%\_env.cmd"
    del /f /q "%TEMP%\_envset.tmp" 2>nul
    del /f /q "%TEMP%\_envget.tmp" 2>nul
    call "%TEMP%\_env.cmd"
    echo | set /p dummy="Done"
    echo .