Reload the path in PowerShell - powershell

Question

If I have an instance of PowerShell ISE running and I install something that modifies the PATH or I modify it in any way outside of PowerShell then I need to restart PowerShell for it to see the updated PATH variable.
Is there a way to reload the path from within PowerShell without restarting it?

Answer 1

Just to bring Rob's comment to light:
$env:Path = [System.Environment]::GetEnvironmentVariable("Path","Machine") + ";" + [System.Environment]::GetEnvironmentVariable("Path","User")

Answer 2

Try getting the machine path and assigning it to the session's path.
$env:Path = [System.Environment]::GetEnvironmentVariable("Path","Machine")

Answer 3

Easiest way, use Chocolatey (freeware). It works for both CMD and PowerShell. Then you will be able to reload PATH (with variable expansion) with a simple command:
refreshenv
Installation from cmd (requires administrator 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

Answer 4

Based on mpen's answer, here is a PowerShell function:
function refresh-path {
$env:Path = [System.Environment]::GetEnvironmentVariable("Path","Machine") +
";" +
[System.Environment]::GetEnvironmentVariable("Path","User")
}
Then just call refresh-path.

Answer 5

Just to add to other answers, you can make sure you don't add superfluous joins by filtering in case the user has an empty path.
$env:Path=(
[System.Environment]::GetEnvironmentVariable("Path","Machine"),
[System.Environment]::GetEnvironmentVariable("Path","User")
) -match '.' -join ';'
Or, more usefully, if you're running a script that adds to a different or multiple environment variables, use a function to reset them all
function resetEnv {
Set-Item `
-Path (('Env:', $args[0]) -join '') `
-Value ((
[System.Environment]::GetEnvironmentVariable($args[0], "Machine"),
[System.Environment]::GetEnvironmentVariable($args[0], "User")
) -match '.' -join ';')
}
resetEnv Path
resetEnv AppPath

Answer 6

If your path contains environment variables that weren't defined at the start of the session, you'll want to expand those too:
$env:Path = [System.Environment]::ExpandEnvironmentVariables([System.Environment]::GetEnvironmentVariable("Path","Machine") + ";" + [System.Environment]::GetEnvironmentVariable("Path","User"))
For me this was useful after installing NVM which defines and adds %NVM_HOME% to the path.
To take this to its logical conclusion you could use this recursive function to expand instead:
function Expand-EnvironmentVariablesRecursively($unexpanded) {
$previous = ''
$expanded = $unexpanded
while($previous -ne $expanded) {
$previous = $expanded
$expanded = [System.Environment]::ExpandEnvironmentVariables($previous)
}
return $expanded
}
And then use:
$env:Path = Expand-EnvironmentVariablesRecursively([System.Environment]::GetEnvironmentVariable("Path","Machine") + ";" + [System.Environment]::GetEnvironmentVariable("Path","User"))
I've opened an issue to add this solution into refreshenv from Chocolatey.