Refresh environment variable

Question

How can I refresh a Windows command shell after I modified my Environment variables?

i.e. In Bash I can just do source ~/.bashrc

Answer 1

I'd like to complete the Lance McCarthy’s answer.

The RefreshEnv.bat is a part of Chocolatey package manager, so if you use Chocolatey then you have RefreshEnv.bat installed. But you can also get this batch file directly from the Chocolatey GitHub (link to raw data). Save this file to your PATH and just run refreshenv from any your console to update environment.

Answer 2

It really depends on how your environment variables were set. If, for example, you used the "SET" command in the command line, it only effects the current instance. On the other hand, commands such as "SETX" will permanently adjust the value of the environment variable. SETX will ensure that all future instances of cmd will see the update. It will not effect the local environment.

If the environment variable is set by another application and is not being updated, it is often easiest to either restart the "explorer.exe" process, log out and back in, or reboot. Essentially, you just need to tell explorer to reload the environment variables. If it is an application that you have developed, such as an installer, ensure that it is calling SendMessage (HWND_BROADCAST, WM_SETTINGCHANGE, 0, (LPARAM)"Environment");. This tells explorer to refresh its cache of the environment variables.

This is important because applications launched by another process inherit their environment variables from their parent. As such, if you launch cmd from explorer, you get the variables as explorer sees them.

Answer 3

I learned there is a much easier way to achieve this: There is a command called refreshenv.

Just run it and you will see the following:

E:>refreshenvewe w Refreshing environment variables eeefrom registry for cmd.exe. Please wait...Finished..

Answer 4

Setting and retreving the master environment in Windows is something that the BartPE people spent a good deal of time on.

The main environment is stored in registry, but the explorer shell reads this to its address. From here it is sent to each cmd.exe session.

SET affects the cmd environment only. SETX allows you to change the master environment, but the setting is not reflected in the local environment.

Frank Westlake's CONSET and 4NT can fetch entries from registry, but no switches for the master environment in particular.

Normally loaded windows keeps track of settings to registry, while the one loaded through minint (ie WinPE) does not. So setting registry and reading registry works in both, but only normally booted windows will see the settings and pass them onto a new cmd,exe program.

Answer 5

This is now significantly easier, no need to restart the shell:

1. Open the start menu and search for RefreshEnv.bat
2. Run RefreshEnv.bat

Observe that your newly added environment variables are available in any new Command/Powershell instance, verifying the refresh.

[EDIT] The batch file comes with certain dev tools (i.e. Visual Studio), it's not a default on Windows. You can quickly get it be installing chocolatey, or even better you can copy the text save it locally https://github.com/chocolatey/choco/blob/master/src/chocolatey.resources/redirects/RefreshEnv.cmd

Answer 6

CMD does not allow to refresh the window to the changes made in the actual session. You have to chainload a new window running a script in any case, no matter the variant you chose.

Since you did not exclude PowerShell as an option, but since it is a given for all actually supported Operating Systems by MicroSoft allow me to add:

Alternatively you could (if you can/are allowed) use PowerShell, which gives you direct access to the actual sessions environment-variables. You may overwrite the specific variables content in $env with the changes you applied to the User/Machine-profile.

[System.Environment]::GetEnvironmentVariable("Path","Machine")

... contains the changes applied to the PATH-environment-variable for the machine-wide profile

[System.Environment]::GetEnvironmentVariable("Path","User")

... contains the changes applied to the PATH-environment-variable for the actual User-profile

So to make these changes immediately effective assign it to the according PATH-environment-variable of the actual session:

$env:Path=[System.Environment]::GetEnvironmentVariable("Path","User")

I found another question on StackOverflow that has some variants to offer for this approach:

PowerShell: Reload the path in powershell

Answer 7

that depends where you "set" your environment variables. the equivalent to your bash example would be like this:

file: env.bat

set FOO=bar

and now you refresh it

% call env.bat

but i think you have done it via the windows-system-settings-dialog (or whatever its name is). the result of this is that you have actually changed the registry. these registry settings are mapped into the process when you launch a new process.

so, you can either start a new process (cmd.exe in your case) OR you can read the registry keys reflecting the changes you want. you could also write a little .bat / .cmd script which gets the environment from the registry and changes the current enviroment accordlingy (if the mood strikes me i ll do this after lunch).

Answer 8

In Win 11 (I haven't confirmed in prior versions of Windows), if you use Control Panel to update the value and save it (search the keyword path in control panel if you don't know were it is) then open a command prompt and execute the command that relies on the PATH and you'll find it has updated. If not, keep in mind command prompt windows which were open before the change was made will not be updated. Close any previously open Command Prompt windows and open a new one. You can of course confirm by typing PATH (in UPPER or lower case) and you should see the full PATH environment variable contents displayed.Image of Control Panel with keyword PATH entered in search bar