PowerShell: Set Environment Variable
This page is a tutorial on using PowerShell to view or set environment variables.
For introduction on Microsoft Windows Environment Variables, see: Windows Environment Variable Tutorial .
Windows environment variable names are case-insensitive.
Environment variable are stored in Windows Registry. [see Windows: Registry Tutorial] When PowerShell starts, it reads the Registry and export them into current session of PowerShell.
- Change to environment variable in current session is temporary. Once you exit shell, the changes are gone.
- Change to environment variable in the registry is permanent.
Adding Path to Path Environment Variable
Environment Variable in Current Session
List Environment Variables
List environment variables:
dir env:
Show env vars whose name contains “path”:
dir env:*path*
Set Environment Variable for current session
Sets a env var named abc for current session:
$env:abc = "alice"
Get value of a env var:
$env:abc
Remove Environment Variable for current session
Deleting a env var from the current session:
rm env:abc
rmis alias ofRemove-Item
Permament Environment Variable
Permanent environment variable is stored in
Windows Registry.
[see PowerShell: Windows Registry]
When PowerShell launches, it reads the registry to get the env vars for the current session.
However, it does not update the registry whenever you create or remove a env var using the env: provider.
To manipulate env var in the registry, use the .NET object like the following:
View
Show env var named “path” of the category “User”:
[environment]::GetEnvironmentVariable("path", "User")
The possible values for the second argument in GetEnvironmentVariable are:
"Process"- Current session of PowerShell.
"User"- Permanent, environment variable for current user. Stored in Registry.
"Machine"- Permanent, environment variable for this machine. Stored in Registry. Require admin privilege.
Create/Set environment variable in Registry
Examples of creating/setting a environment variable:
[Environment]::SetEnvironmentVariable("xx", "123", "User") # or [Environment]::SetEnvironmentVariable("xx", "123", "Machine")
The syntax [Environment]::SetEnvironmentVariable means calling the .NET object “Environment” and using its method “SetEnvironmentVariable”.
Note: all arguments should be string.
Remove environment variable in Registry
# removing a env var from registry [Environment]::SetEnvironmentVariable("xyz", $null, "User") # or [Environment]::SetEnvironmentVariable("xyz", $null, "Machine")
Refresh
changes of environment variable in registry is not reflected in current PowerShell session. type exit to exit PowerShell, then start a new session.