about_Environment_Provider
Provider name
Environment
Drives
Env:
Capabilities
ShouldProcess
Short description
Provides access to the Windows environment variables.
Detailed description
The PowerShell Environment provider lets you get, add, change, clear, and delete environment variables and values in PowerShell.
Environment variables are dynamically named variables that describe the environment in which your programs run. Windows and PowerShell use environment variables to store persistent information that affect system and process execution. Unlike PowerShell variables, environment variables are not subject to scope constraints.
The Environment drive is a flat namespace containing the environment variables specific to the current user's session. The environment variables have no child items.
The Environment provider supports the following cmdlets, which are covered in this article.
Types exposed by this provider
Each environment variable is an instance of the System.Collections.DictionaryEntry class. The name of the variable is the dictionary key. The value of the environment variable is the dictionary value.
Navigating the Environment drive
The Environment provider exposes its data store in the Env: drive. To
work with environment variables, change your location to the Env: drive
(Set-Location Env:), or work from another PowerShell drive. To reference an
environment variable from another location, use the Env: drive name in the
path.
Set-Location Env:
To return to a file system drive, type the drive name. For example, type:
Set-Location C:
You can also work with the Environment provider from any other PowerShell
drive. To reference an environment variable from another location, use the drive name Env: in the path.
The Environment provider also exposes environment variables using a variable
prefix of $env:. The following command views the contents of the
ProgramFiles environment variable. The $env: variable prefix can
be used from any PowerShell drive.
PS C:\> $env:ProgramFiles
C:\Program Files
You can also change the value of an environment variable using the $env:
variable prefix. Any changes made only pertain to the current PowerShell
session for as long as it is active.
Note
PowerShell uses aliases to allow you a familiar way to work with provider
paths. Commands such as dir and ls are now aliases for
Get-ChildItem,
cd is an alias for Set-Location. and pwd is
an alias for Get-Location.
Getting environment variables
This command lists all the environment variables in the current session.
Get-Item -Path Env:
You can use this command from any PowerShell drive.
The Environment provider has no containers, so the above command has the
same effect when used with Get-ChildItem.
Get-ChildItem -Path Env:
Get a selected environment variable
This command gets the WINDIR environment Variable.
Get-ChildItem -Path Env:windir
You can also use the variable prefix format as well.
$env:windir
Create an environment variable
This command creates the USERMODE environment variable with a value of
"Non-Admin". The -Path parameter value creates the new item in the Env:
drive. The new environment variable is only usable in the current PowerShell
session for as long as it is active.
PS C:\> New-Item -Path Env: -Name USERMODE -Value Non-Admin
Changing an environment variable
Rename an environment variable
This command uses the Rename-Item cmdlet to change the name of the USERMODE
environment variable that you created to USERROLE. Do not change the name of
an environment variable that the system uses. Although these changes affect
only the current session, they might cause the system or a program to operate
incorrectly.
Rename-Item -Path Env:USERMODE -NewName USERROLE
Change an environment variable
This command uses the Set-Item cmdlet to change the value of the USERROLE
environment variable to "Administrator".
Set-Item -Path Env:USERROLE -Value Administrator
Copy an environment variable
This command copies the value of the USERROLE environment variable to the
USERROLE2 environment Variable.
Copy-Item -Path Env:USERROLE -Destination Env:USERROLE2
Remove an environment variable
This command deletes the USERROLE2 environment variable from the current
session.
Remove-Item -Path Env:USERROLE2
Remove an environment variable with Clear-Item
This command deletes the USERROLE environment variable by clearing its
value.
Clear-Item -Path Env:USERROLE
Using the pipeline
Provider cmdlets accept pipeline input. You can use the pipeline to simplify task by sending provider data from one cmdlet to another provider cmdlet. To read more about how to use the pipeline with provider cmdlets, see the cmdlet references provided throughout this article.
Getting help
Beginning in Windows PowerShell 3.0, you can get customized help topics for provider cmdlets that explain how those cmdlets behave in a file system drive.
To get the help topics that are customized for the file system drive, run a
Get-Help command in a file system drive or use the -Path
parameter of Get-Help to specify a file system drive.
Get-Help Get-ChildItem
Get-Help Get-ChildItem -Path env:
See also
PowerShell