Where are environment variables stored in the Windows Registry?

I need to access an environment variable remotely. To do this, I think the best way is to read it from registry.

Where are environment variables stored in the Windows Registry?

Here's where they're stored on Windows XP through Windows Server 2012 R2:

User Variables

HKEY_CURRENT_USER\Environment

System Variables

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment

There is a more efficient way of doing this in Windows 7. SETX is installed by default and supports connecting to other systems.

To modify a remote system's global environment variables, you would use

setx /m /s HOSTNAME-GOES-HERE VariableNameGoesHere VariableValueGoesHere

This does not require restarting Windows Explorer.

> /M Specifies that the variable should be set in the system wide (HKEY_LOCAL_MACHINE) environment. The default is to set the variable under the HKEY_CURRENT_USER environment.

> /S system Specifies the remote system to connect to.

CMD:

reg query "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment"
reg query HKEY_CURRENT_USER\Environment

PowerShell:

Get-Item "HKLM:\SYSTEM\CurrentControlSet\Control\Session Manager\Environment"
Get-Item HKCU:\Environment

Powershell/.NET: (see EnvironmentVariableTarget Enum)

[System.Environment]::GetEnvironmentVariables([System.EnvironmentVariableTarget]::Machine)
[System.Environment]::GetEnvironmentVariables([System.EnvironmentVariableTarget]::User)

I always had problems with that, and I made a getx.bat script:

:: getx %envvar% [\m]
:: Reads envvar from user environment variable and stores it in the getxvalue variable
:: with \m read system environment

@SETLOCAL EnableDelayedExpansion
@echo OFF

@set l_regpath="HKEY_CURRENT_USER\Environment"
@if "\m"=="%2" set l_regpath="HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment"

::REG ADD "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment" /v PATH /t REG_SZ /f /d "%PATH%"
::@REG QUERY %l_regpath% /v %1 /S

@FOR /F "tokens=*" %%A IN ('REG QUERY %l_regpath% /v %1 /S') DO (
@  set l_a=%%A
@    if NOT "!l_a!"=="!l_a:    =!" set l_line=!l_a!
)

:: Delimiter is four spaces. Change it to tab \t
@set l_line=!l_line!
@set l_line=%l_line:    =    %

@set getxvalue=

@FOR /F "tokens=3* delims=	" %%A IN ("%l_line%") DO (
@    set getxvalue=%%A
)
@set getxvalue=!getxvalue!
@echo %getxvalue% > getxfile.tmp.txt
@ENDLOCAL

:: We already used tab as a delimiter
@FOR /F "delims=    " %%A IN (getxfile.tmp.txt) DO (
    @set getxvalue=%%A
)
@del getxfile.tmp.txt

@echo ON