Refresh environment variable

Solution 1:

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.

Solution 2:

I'd like to complete the Lance McCarthy 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.

Solution 3:

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.