How can I refresh the PATH environment variable in a Batch script

Question

I have a batch file "file.bat" that will call an installer with the following command:

msiexec.exe /i "%~dp0\installer.msi"

The installer will install a program and update the Path variable. While this works fine, the problem is when I try to start the program it's not found because apparently the PATH variable was not updated. I tried restarting the batch file from within itself with:

start cmd /c file.bat 

but it didn't work. Is there a way to refresh the PATH variable or maybe restart the batch file in a new process so that it detects the new environment?

PS: restarting the batch file manually works of course but it's not what I want.

Thanks.

Supplemental

set path=%path%;C:\Some other folder – Turmoil

I think it may be useful if you posted the entire file.bat. – Insincerity

You have to read the system PATH value just modified by the installer directly from registry either with command reg or with command setx and update/replace local PATH with new system PATH. See for example answer on Why are other folder paths also added to system PATH with SetX and not only the specified folder path? how to get system PATH directly from registry. – Amiss

Thank you for the suggestions. I ended up using the solution from here: #172088 It needs an extra file to work. It's weird that this can't be solved more easily! – Supplemental

Answer 1

Easiest way, use Chocolatey (freeare). Then you will be able to reload PATH (with variable expansion) with a simple command:

refreshenv

Installation from cmd (requires admin rights):

@"%SystemRoot%\System32\WindowsPowerShell\v1.0\powershell.exe" -NoProfile -InputFormat None -ExecutionPolicy Bypass -Command "iex ((New-Object System.Net.WebClient).DownloadString('https://chocolatey.org/install.ps1'))" && SET "PATH=%PATH%;%ALLUSERSPROFILE%\chocolatey\bin"

Example usage:

> SET JAVA_HOME=c:/java/jdk6
> SET PATH=%JAVA_HOME%/bin
> ECHO %PATH%
c:/java/jdk6/bin

> SET JAVA_HOME=c:/java/jdk8
> refreshenv
Refreshing environment variables from registry for cmd.exe. Please wait...Finished..
> echo %PATH%
c:/java/jdk8/bin

Guillermo

Answer 2

IN Windows PowerShell exit and run again

Lambeth

Answer 3

simple batch file that refreshes the %path% environment variable:

@echo off
echo.
echo Refreshing PATH from registry

:: Get System PATH
for /f "tokens=3*" %%A in ('reg query "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Environment" /v Path') do set syspath=%%A%%B

:: Get User Path
for /f "tokens=3*" %%A in ('reg query "HKCU\Environment" /v Path') do set userpath=%%A%%B

:: Set Refreshed Path
set PATH=%userpath%;%syspath%

echo Refreshed PATH
echo %PATH%

Denim

It is a good answer J03L, but the problem is when I set path like this: JAVA_7 = C:\Program Files\Java\jdk1.7xxxx JAVA_8 = C:\Program Files\Java\jdk1.8xxxx JAVA_HOME = %JAVA_8% Path = %JAVA_HOME%\bin;%MAVEN_HOME%\bin Because this will generate a PATH with %JAVA_8%\bin;C:\windows\System32\WindowsPowerShell\v1.0\;C:\windows\idmu\common;etc. Do you think it's possible to change the batch file to generate a second level variable substituion on user variables? Just curious, still a nice answer tho! – Vasodilator

For some reason, not all spaces in a path are preserved (i.e. the original path shows 'Program Files (x86)', but the set variable shows 'ProgramFiles (x86)' ). – Soup

I believe this part set userpath=%%A%%B should really be set userpath=%%A %%B (notice additional space). – Salyer

Answer 4

To reset the path within a Windows batch script, you can output the system environment variables from powershell and assign the output to the path as follows:

for /f "tokens=* usebackq" %%p in (powershell -Command "& {[System.Environment]::GetEnvironmentVariable('Path','Machine') + ';' + [System.Environment]::GetEnvironmentVariable('Path','User')}") do (set path=%%p)

Acetylate