Setting Windows PowerShell environment variables

If, some time during a PowerShell session, you need to see or to temporarily modify the PATH environment variable , you can type one of these commands:

$env:Path                             # shows the actual content
$env:Path = 'C:\foo;' + $env:Path     # attach to the beginning
$env:Path += ';C:\foo'                # attach to the end

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Changing the actual environment variables can be done by using the env: namespace / drive information. For example, this code will update the path environment variable:

$env:Path = "SomeRandomPath";             (replaces existing path) 
$env:Path += ";SomeRandomPath"            (appends to existing path)

Making change permanent

There are ways to make environment settings permanent, but if you are only using them from PowerShell, it's probably a lot better to use Powershell profiles script.

Everytime a new instance of Powershell starts, it look for specific script files (named profile files) and execute them if they do exist. You can edit one of these profile to customize your enviroment.

To know where those profile scripts are located in your computer type:

$profile                                     
$profile.AllUsersAllHosts           
$profile.AllUsersCurrentHost        
$profile.CurrentUserAllHosts    
$profile.CurrentUserCurrentHost     

You can edit one of them, for example, by typing:

notepad $profile

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You can also modify user/system environment variables permanently (i.e. will be persistent across shell restarts) with the following:

Modify a system environment variable

[Environment]::SetEnvironmentVariable
     ("Path", $env:Path, [System.EnvironmentVariableTarget]::Machine)

Modify a user environment variable

[Environment]::SetEnvironmentVariable
     ("INCLUDE", $env:INCLUDE, [System.EnvironmentVariableTarget]::User)

Usage from comments - add to the system environment variable

[Environment]::SetEnvironmentVariable(
    "Path",
    [Environment]::GetEnvironmentVariable("Path", [EnvironmentVariableTarget]::Machine) + ";C:\bin",
    [EnvironmentVariableTarget]::Machine)

String based solution is also possible if you don't want to write types

[Environment]::SetEnvironmentVariable("Path", $env:Path + ";C:\bin", "Machine")

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WARNING: save a copy of your existing path by doing $env:path >> a.out in a PowerShell prompt, in case something goes wrong.

From the PowerShell prompt:

setx PATH "$env:path;\the\directory\to\add" -m

You should then see the text:

SUCCESS: Specified value was saved.

Restart your session, and the variable will be available. setx can also be used to set arbitrary variables. Type setx /? at the prompt for documentation.

---

Like JeanT's answer, I wanted an abstraction around adding to the path. Unlike JeanT's answer I needed it to run without user interaction. Other behavior I was looking for:

Updates $env:Path so the change takes effect in the current session

Persists the environment variable change for future sessions

Doesn't add a duplicate path when the same path already exists

In case it's useful, here it is:

function Add-EnvPath {
    param(
        [Parameter(Mandatory=$true)]
        [string] $Path,

        [ValidateSet('Machine', 'User', 'Session')]
        [string] $Container = 'Session'
    )

    if ($Container -ne 'Session') {
        $containerMapping = @{
            Machine = [EnvironmentVariableTarget]::Machine
            User = [EnvironmentVariableTarget]::User
        }
        $containerType = $containerMapping[$Container]

        $persistedPaths = [Environment]::GetEnvironmentVariable('Path', $containerType) -split ';'
        if ($persistedPaths -notcontains $Path) {
            $persistedPaths = $persistedPaths + $Path | where { $_ }
            [Environment]::SetEnvironmentVariable('Path', $persistedPaths -join ';', $containerType)
        }
    }

    $envPaths = $env:Path -split ';'
    if ($envPaths -notcontains $Path) {
        $envPaths = $envPaths + $Path | where { $_ }
        $env:Path = $envPaths -join ';'
    }
}

Check out my gist for the corresponding Remove-EnvPath function.

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NOTE 1: run these commands on eleveted powershell(e.g. with administrator privileges)

NOTE 2: after every step to make your commands work close the session and open it again

do not make headaches for yourself, want a simple, one line solution to:

add a permanent environment variable:

[Environment]::SetEnvironmentVariable("NewEnvVar", "NewEnvValue", "Machine")

modify/change that:

[Environment]::SetEnvironmentVariable("oldEnvVar", "NewEnvValue", "Machine")

delete/remove that:

[Environment]::SetEnvironmentVariable("oldEnvVar", "", "Machine")

---

Although the current accepted answer works in the sense that the path variable gets permanently updated from the context of PowerShell, it doesn't actually update the environment variable stored in the Windows registry.

To achieve that, you can obviously use PowerShell as well:

$oldPath=(Get-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Environment' -Name PATH).Path

$newPath=$oldPath+’;C:\NewFolderToAddToTheList\’

Set-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Environment' -Name PATH –Value $newPath

More information is in blog post Use PowerShell to Modify Your Environmental Path

If you use PowerShell community extensions, the proper command to add a path to the environment variable path is:

Add-PathVariable "C:\NewFolderToAddToTheList" -Target Machine

---

All the answers suggesting a permanent change have the same problem: They break the path registry value.

SetEnvironmentVariable turns the REG_EXPAND_SZ value %SystemRoot%\system32 into a REG_SZ value of C:\Windows\system32.

Any other variables in the path are lost as well. Adding new ones using %myNewPath% won't work any more.

Here's a script Set-PathVariable.ps1 that I use to address this problem:

 [CmdletBinding(SupportsShouldProcess=$true)]
 param(
     [parameter(Mandatory=$true)]
     [string]$NewLocation)

 Begin
 {

 #requires –runasadministrator

     $regPath = "SYSTEM\CurrentControlSet\Control\Session Manager\Environment"
     $hklm = [Microsoft.Win32.Registry]::LocalMachine

     Function GetOldPath()
     {
         $regKey = $hklm.OpenSubKey($regPath, $FALSE)
         $envpath = $regKey.GetValue("Path", "", [Microsoft.Win32.RegistryValueOptions]::DoNotExpandEnvironmentNames)
         return $envPath
     }
 }

 Process
 {
     # Win32API error codes
     $ERROR_SUCCESS = 0
     $ERROR_DUP_NAME = 34
     $ERROR_INVALID_DATA = 13

     $NewLocation = $NewLocation.Trim();

     If ($NewLocation -eq "" -or $NewLocation -eq $null)
     {
         Exit $ERROR_INVALID_DATA
     }

     [string]$oldPath = GetOldPath
     Write-Verbose "Old Path: $oldPath"

     # Check whether the new location is already in the path
     $parts = $oldPath.split(";")
     If ($parts -contains $NewLocation)
     {
         Write-Warning "The new location is already in the path"
         Exit $ERROR_DUP_NAME
     }

     # Build the new path, make sure we don't have double semicolons
     $newPath = $oldPath + ";" + $NewLocation
     $newPath = $newPath -replace ";;",""

     if ($pscmdlet.ShouldProcess("%Path%", "Add $NewLocation")){

         # Add to the current session
         $env:path += ";$NewLocation"

         # Save into registry
         $regKey = $hklm.OpenSubKey($regPath, $True)
         $regKey.SetValue("Path", $newPath, [Microsoft.Win32.RegistryValueKind]::ExpandString)
         Write-Output "The operation completed successfully."
     }

     Exit $ERROR_SUCCESS
 }

I explain the problem in more detail in a blog post.

---

This sets the path for the current session and prompts the user to add it permanently:

function Set-Path {
    param([string]$x)
    $Env:Path+= ";" +  $x
    Write-Output $Env:Path
    $write = Read-Host 'Set PATH permanently ? (yes|no)'
    if ($write -eq "yes")
    {
        [Environment]::SetEnvironmentVariable("Path",$env:Path, [System.EnvironmentVariableTarget]::User)
        Write-Output 'PATH updated'
    }
}

You can add this function to your default profile, (Microsoft.PowerShell_profile.ps1), usually located at %USERPROFILE%\Documents\WindowsPowerShell.

---

Building on @Michael Kropat's answer I added a parameter to prepend the new path to the existing PATHvariable and a check to avoid the addition of a non-existing path:

function Add-EnvPath {
    param(
        [Parameter(Mandatory=$true)]
        [string] $Path,

        [ValidateSet('Machine', 'User', 'Session')]
        [string] $Container = 'Session',

        [Parameter(Mandatory=$False)]
        [Switch] $Prepend
    )

    if (Test-Path -path "$Path") {
        if ($Container -ne 'Session') {
            $containerMapping = @{
                Machine = [EnvironmentVariableTarget]::Machine
                User = [EnvironmentVariableTarget]::User
            }
            $containerType = $containerMapping[$Container]

            $persistedPaths = [Environment]::GetEnvironmentVariable('Path', $containerType) -split ';'
            if ($persistedPaths -notcontains $Path) {
                if ($Prepend) {
                    $persistedPaths = ,$Path + $persistedPaths | where { $_ }
                    [Environment]::SetEnvironmentVariable('Path', $persistedPaths -join ';', $containerType)
                }
                else {
                    $persistedPaths = $persistedPaths + $Path | where { $_ }
                    [Environment]::SetEnvironmentVariable('Path', $persistedPaths -join ';', $containerType)
                }
            }
        }

        $envPaths = $env:Path -split ';'
        if ($envPaths -notcontains $Path) {
            if ($Prepend) {
                $envPaths = ,$Path + $envPaths | where { $_ }
                $env:Path = $envPaths -join ';'
            }
            else {
                $envPaths = $envPaths + $Path | where { $_ }
                $env:Path = $envPaths -join ';'
            }
        }
    }
}

---

My suggestion is this one:

I have tested this to add C:\oracle\x64\bin to environment variable Path permanently and this works fine.

$ENV:PATH

The first way is simply to do:

$ENV:PATH=”$ENV:PATH;c:\path\to\folder”

But this change isn’t permanent. $env:path will default back to what it was before as soon as you close your PowerShell terminal and reopen it again. That’s because you have applied the change at the session level and not at the source level (which is the registry level). To view the global value of $env:path, do:

Get-ItemProperty -Path ‘Registry::HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Environment’ -Name PATH

Or more specifically:

(Get-ItemProperty -Path ‘Registry::HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Environment’ -Name PATH).path

Now to change this, first we capture the original path that needs to be modified:

$oldpath = (Get-ItemProperty -Path ‘Registry::HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Environment’ -Name PATH).path

Now we define what the new path should look like. In this case we are appending a new folder:

$newpath = “$oldpath;c:\path\to\folder”

Note: Be sure that the $newpath looks how you want it to look. If not, then you could damage your OS.

Now apply the new value:

Set-ItemProperty -Path ‘Registry::HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Environment’ -Name PATH -Value $newPath

Now do one final check that it looks like how you expect it to:

(Get-ItemProperty -Path ‘Registry::HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Environment’ -Name PATH).Path

You can now restart your PowerShell terminal (or even reboot the machine) and see that it doesn’t rollback to its old value again.

Note the ordering of the paths may change so that it’s in alphabetical order, so make sure you check the whole line. To make it easier, you can split the output into rows by using the semi-colon as a delimiter:

($env:path).split(“;”)

---

Only the answers that push the value into the registry affect a permanent change (so the majority of answers on this thread, including the accepted answer, do not permanently affect the Path).

The following function works for both Path / PSModulePath and for User / System types. It will also add the new path to the current session by default.

function AddTo-Path {
    param ( 
        [string]$PathToAdd,
        [Parameter(Mandatory=$true)][ValidateSet('System','User')][string]$UserType,
        [Parameter(Mandatory=$true)][ValidateSet('Path','PSModulePath')][string]$PathType
    )

    # AddTo-Path "C:\XXX" "PSModulePath" 'System' 
    if ($UserType -eq "System" ) { $RegPropertyLocation = 'HKLM:\System\CurrentControlSet\Control\Session Manager\Environment' }
    if ($UserType -eq "User"   ) { $RegPropertyLocation = 'HKCU:\Environment' } # also note: Registry::HKEY_LOCAL_MACHINE\ format
    $PathOld = (Get-ItemProperty -Path $RegPropertyLocation -Name $PathType).$PathType
    "`n$UserType $PathType Before:`n$PathOld`n"
    $PathArray = $PathOld -Split ";" -replace "\\+$", ""
    if ($PathArray -notcontains $PathToAdd) {
        "$UserType $PathType Now:"   # ; sleep -Milliseconds 100   # Might need pause to prevent text being after Path output(!)
        $PathNew = "$PathOld;$PathToAdd"
        Set-ItemProperty -Path $RegPropertyLocation -Name $PathType -Value $PathNew
        Get-ItemProperty -Path $RegPropertyLocation -Name $PathType | select -ExpandProperty $PathType
        if ($PathType -eq "Path") { $env:Path += ";$PathToAdd" }                  # Add to Path also for this current session
        if ($PathType -eq "PSModulePath") { $env:PSModulePath += ";$PathToAdd" }  # Add to PSModulePath also for this current session
        "`n$PathToAdd has been added to the $UserType $PathType"
    }
    else {
        "'$PathToAdd' is already in the $UserType $PathType. Nothing to do."
    }
}

# Add "C:\XXX" to User Path (but only if not already present)
AddTo-Path "C:\XXX" "User" "Path"

# Just show the current status by putting an empty path
AddTo-Path "" "User" "Path"

---

As Jonathan Leaders mentioned here, it is important to run the command/script elevated to be able to change environment variables for 'machine', but running some commands elevated doesn't have to be done with the Community Extensions, so I'd like to modify and extend JeanT's answer in a way, that changing machine variables also can be performed even if the script itself isn't run elevated:

function Set-Path ([string]$newPath, [bool]$permanent=$false, [bool]$forMachine=$false )
{
    $Env:Path += ";$newPath"

    $scope = if ($forMachine) { 'Machine' } else { 'User' }

    if ($permanent)
    {
        $command = "[Environment]::SetEnvironmentVariable('PATH', $env:Path, $scope)"
        Start-Process -FilePath powershell.exe -ArgumentList "-noprofile -command $Command" -Verb runas
    }

}

---

Within PowerShell, one can navigate to the environment variable directory by typing:

Set-Location Env:

This will bring you to the Env:> directory. From within this directory:

To see all environment variables, type:

Env:\> Get-ChildItem

To see a specific environment variable, type:

Env:\> $Env:<variable name>, e.g. $Env:Path

To set an environment variable, type:

Env:\> $Env:<variable name> = "<new-value>", e.g. $Env:Path="C:\Users\"

To remove an environment variable, type:

Env:\> remove-item Env:<variable name>, e.g. remove-item Env:SECRET_KEY

More information is in About Environment Variables.

---

Most answers aren't addressing UAC. This covers UAC issues.

First install PowerShell Community Extensions: choco install pscx via http://chocolatey.org/ (you may have to restart your shell environment).

Then enable pscx

Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser #allows scripts to run from the interwebs, such as pcsx

Then use Invoke-Elevated

Invoke-Elevated {Add-PathVariable $args[0] -Target Machine} -ArgumentList $MY_NEW_DIR

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To be clear, the 1990's Windows way of click on Start, right click on This PC, and choose Properties, and then select Advanced system settings, and then in the dialog box that pops up, select Environment Variables, and in the list double clicking on PATH and then using the New, Edit, Move Up and Move Down all still work for changing the PATH. Power shell, and the rest of Windows get whatever you set here.

Yes you can use these new methods, but the old one still works. And at the base level all of the permanent change methods are controlled ways of editing your registry files.

---

Open PowerShell and run:

[Environment]::SetEnvironmentVariable("PATH", "$ENV:PATH;<path to exe>", "USER")

---

I tried to optimise SBF's and Michael's code a bit to make it more compact.

I am relying on PowerShell's type coercion where it automatically converts strings to enum values, so I didn't define the lookup dictionary.

I also pulled out the block that adds the new path to the list based on a condition, so that work is done once and stored in a variable for re-use.

It is then applied permanently or just to the Session depending on the $PathContainer parameter.

We can put the block of code in a function or a ps1 file that we call directly from the command prompt. I went with DevEnvAddPath.ps1.

param(
    [Parameter(Position=0,Mandatory=$true)][String]$PathChange,

    [ValidateSet('Machine', 'User', 'Session')]
    [Parameter(Position=1,Mandatory=$false)][String]$PathContainer='Session',
    [Parameter(Position=2,Mandatory=$false)][Boolean]$PathPrepend=$false
)

[String]$ConstructedEnvPath = switch ($PathContainer) { "Session"{${env:Path};} default{[Environment]::GetEnvironmentVariable('Path', $containerType);} };
$PathPersisted = $ConstructedEnvPath -split ';';

if ($PathPersisted -notcontains $PathChange) {
    $PathPersisted = $(switch ($PathPrepend) { $true{,$PathChange + $PathPersisted;} default{$PathPersisted + $PathChange;} }) | Where-Object { $_ };

    $ConstructedEnvPath = $PathPersisted -join ";";
}

if ($PathContainer -ne 'Session') 
{
    # Save permanently to Machine, User
    [Environment]::SetEnvironmentVariable("Path", $ConstructedEnvPath, $PathContainer);
}

# Update the current session
${env:Path} = $ConstructedEnvPath;

I do something similar for a DevEnvRemovePath.ps1.

param(
    [Parameter(Position=0,Mandatory=$true)][String]$PathChange,

    [ValidateSet('Machine', 'User', 'Session')]
    [Parameter(Position=1,Mandatory=$false)][String]$PathContainer='Session'
)

[String]$ConstructedEnvPath = switch ($PathContainer) { "Session"{${env:Path};} default{[Environment]::GetEnvironmentVariable('Path', $containerType);} };
$PathPersisted = $ConstructedEnvPath -split ';';

if ($PathPersisted -contains $PathChange) {
    $PathPersisted = $PathPersisted | Where-Object { $_ -ne $PathChange };

    $ConstructedEnvPath = $PathPersisted -join ";";
}

if ($PathContainer -ne 'Session') 
{
    # Save permanently to Machine, User
    [Environment]::SetEnvironmentVariable("Path", $ConstructedEnvPath, $PathContainer);
}

# Update the current session
${env:Path} = $ConstructedEnvPath;

So far, they seem to work.

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Lots of examples of appending, or overwriting. Here is an example of prepending a path on powershell for Linux, Ubuntu 18.04 with pwsh 7.1.3

$ENV:PATH = "/home/linuxbrew/.linuxbrew/bin:$ENV:PATH"

I'm specifically adding the linuxbrew (homebrew for linux) bin directory to take precedence over the system installed. It helped solve an issue I was having and although this was the most helpful place, it also left me "experimenting".

Note that the : is Linux path separator, whereas on Windows (or at least my windows) you would use ; for powershell typically.

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Editing the registry key in @ali Darabi's answer worked best for me, but When I didn't have the right permissions to do it from Powershell. So I edited it directly in regedit.

I want to expand further on the subject in this answer.

Restarting Powershell also wasn't sufficient to propagate the change. I had to Open Task Manager and restart explorer.exe to trigger a reload of the registry.

It can be quite tedious to navigate the registry so in order to maintain an user friendly experience you can execute this from Powershell:

REG ADD "HKCU\Software\Microsoft\Windows\CurrentVersion\Applets\Regedit" /v "LastKey" /d "HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Environment" /f; regedit

It sets the last opened window to a certain registry path, so that when you open regedit the next time it opens at the proper key.

---

If you need to set variable name dynamically and for session only, then use:

New-Item env:\$key -Value $value -Force | Out-Null

---