Set-Variable

Set-Variable [-Name*] <String[]> [[-Value] <Object>] [-Confirm] [-Description <String>] [-Exclude <String[]>][-Force] [-Include <String[]>] [-Option {None | ReadOnly | Constant | Private | AllScope | Unspecified}][-PassThru] [-Scope <String>] [-Visibility {Public | Private}] [-WhatIf] [<CommonParameters>]

The Set-Variable cmdlet assigns a value to a specified variable or changes the current value. If the variable does not exist, the cmdlet creates it.

Parameters

-Confirm [<SwitchParameter>]

Default value is False
Accepts pipeline input False

Prompts you for confirmation before running the cmdlet.

-Description <String>

Default value is None
Accepts pipeline input False

Specifies the description of the variable.

-Exclude <String[]>

Default value is None
Accepts pipeline input False

Specifies an array of items that this cmdlet excludes from the operation. The value of this parameter qualifies the Path parameter. Enter a path element or pattern, such as `*.txt`. Wildcards are permitted.

-Force [<SwitchParameter>]

Default value is False
Accepts pipeline input False

Forces the command to run without asking for user confirmation.

By default, you can overwrite a variable, unless the variable has an option value of ReadOnly or Constant.

-Include <String[]>

Default value is None
Accepts pipeline input False

Specifies an array of items that this cmdlet includes in the operation. The value of this parameter qualifies the Name parameter. Enter a name or name pattern, such as `c*`. Wildcards are permitted.

-Name <String[]>

This value is required
Default value is None
Accepts pipeline input ByPropertyName

Specifies the variable name.

-Option <ScopedItemOptions>

Default value is None
Accepts pipeline input False

Specifies the value of the Options property of the variable.

The acceptable values for this parameter are:

- None. Sets no options. ("None" is the default.) - ReadOnly. Can be deleted. Cannot be not changed, except by using the Force parameter. - Constant. Cannot be deleted or changed. Constant is valid only when you are creating a variable. You cannot change the options of an existing variable to Constant. - Private. The variable is available only in the current scope. - AllScope. The variable is copied to any new scopes that are created.

To see the Options property of all variables in the session, type `Get-Variable | Format-Table -Property name, options -Autosize`.

-PassThru [<SwitchParameter>]

Default value is False
Accepts pipeline input False

Returns an object representing the item with which you are working. By default, this cmdlet does not generate any output.

-Scope <String>

Default value is None
Accepts pipeline input False

Specifies the scope of the variable.The acceptable values for this parameter are:

- Global

- Local

- Script

- A number relative to the current scope (0 through the number of scopes, where 0 is the current scope and 1 is its parent).

Local is the default.

-Value <Object>

Default value is None
Accepts pipeline input ByPropertyName

Specifies the value of the variable.

-Visibility <SessionStateEntryVisibility>

Default value is None
Accepts pipeline input False

Determines whether the variable is visible outside of the session in which it was created. This parameter is designed for use in scripts and commands that will be delivered to other users. The acceptable values for this parameter are:

- Public. The variable is visible. (Public is the default.) - Private. The variable is not visible.

When a variable is private, it does not appear in lists of variables, such as those returned by Get-Variable, or in displays of the Variable: drive. Commands to read or change the value of a private variable return an error. However, the user can run commands that use a private variable if the commands were written in the session in which the variable was defined.

-WhatIf [<SwitchParameter>]

Default value is False
Accepts pipeline input False

Shows what would happen if the cmdlet runs. The cmdlet is not run.

<CommonParameters>

This cmdlet supports the common parameters: Verbose, Debug,ErrorAction, ErrorVariable, WarningAction, WarningVariable,OutBuffer, PipelineVariable, and OutVariable.

Inputs

System.Object

You can pipe an object that represents the value of the variable to Set-Variable .

Outputs

None or System.Management.Automation.PSVariable

When you use the PassThru parameter, Set-Variable generates a System.Management.Automation.PSVariable object representing the new or changed variable. Otherwise, this cmdlet does not generate any output.

Examples

Set a variable and get its value:
```
PS C:\> Set-Variable -Name "desc" -Value "A description"
PS C:\> Get-Variable -Name "desc"
```
These commands set the value of the desc variable to A description, and then gets the value of the variable.
Set a global, read-only variable:
```
PS C:\> Set-Variable -Name "processes" -Value (Get-Process) -Option constant -Scope global -Description "All processes" -PassThru | Format-List -Property *
```
This command creates a global, read-only variable that contains all processes on the system, and then it displays all properties of the variable.

The command uses the Set-Variable cmdlet to create the variable. It uses the PassThru parameter to create an object representing the new variable, and it uses the pipeline operator (|) to pass the object to the Format-List cmdlet. It uses the Property parameter of Format-List with a value of all (*) to display all properties of the newly created variable.

The value, "(Get-Process)", is enclosed in parentheses to ensure that it is executed before being stored in the variable. Otherwise, the variable contains the words "Get-Process".

Understand public vs. private variables:

PS C:\> # Set-Variable -Name "counter" -Visibility Private
PS C:\> New-Variable -Name "counter" -Visibility Public -Value 26
PS C:\> $Counter
26 PS C:\> Get-Variable c*

   Name Value
   ---- -----
   Culture en-US
   ConsoleFileName
   ConfirmPreference High
   CommandLineParameters {}
   Counter 26 PS C:\>Set-Variable -Name "counter" -Visibility Private

PS C:\> Get-Variable c*

   Name Value
   ---- -----
   Culture en-US
   ConsoleFileName
   ConfirmPreference High
   CommandLineParameters {} PS C:\>$counter
   "Cannot access the variable '$counter' because it is a private variable" PS C:\>.\use-counter.ps1
   #Commands completed successfully.

This command shows how to change the visibility of a variable to Private. This variable can be read and changed by scripts with the required permissions, but it is not visible to the user.

The sample output shows the difference in the behavior of public and private variables.

Additional Notes

This work is licensed under a Creative Commons Attribution 4.0 International. It is attributed to Microsoft Corporation and can be found here.

PowerShell Commands