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Set-Variable

  • Reference
Module:
Microsoft.PowerShell.Utility

Sets the value of a variable. Creates the variable if one with the requested name does not exist.

Syntax

Set-Variable
   [-Name] <String[]>
   [[-Value] <Object>]
   [-Include <String[]>]
   [-Exclude <String[]>]
   [-Description <String>]
   [-Option <ScopedItemOptions>]
   [-Force]
   [-Visibility <SessionStateEntryVisibility>]
   [-PassThru]
   [-Scope <String>]
   [-WhatIf]
   [-Confirm]
   [<CommonParameters>]

Description

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.

Examples

Example 1: 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.

Example 2: 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".

Example 3: Understand public vs. private variables

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.

Parameters

-Confirm

Prompts you for confirmation before running the cmdlet.

Type:SwitchParameter
Aliases:cf
Position:Named
Default value:False
Required:False
Accept pipeline input:False
Accept wildcard characters:False

-Description

Specifies the description of the variable.

Type:String
Position:Named
Default value:None
Required:False
Accept pipeline input:False
Accept wildcard characters:False

-Exclude

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.

Type:String[]
Position:Named
Default value:None
Required:False
Accept pipeline input:False
Accept wildcard characters:True

-Force

Allows you to create a variable with the same name as an existing read-only variable, or to change the value of a read-only variable.

By default, you can overwrite a variable, unless the variable has an option value of ReadOnly or Constant. For more information, see the Option parameter.

Type:SwitchParameter
Position:Named
Default value:False
Required:False
Accept pipeline input:False
Accept wildcard characters:False

-Include

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.

Type:String[]
Position:Named
Default value:None
Required:False
Accept pipeline input:False
Accept wildcard characters:True

-Name

Specifies the variable name.

Type:String[]
Position:0
Default value:None
Required:True
Accept pipeline input:True
Accept wildcard characters:False

-Option

Specifies the value of the Options property of the variable.

Valid values are:

  • None: Sets no options. ("None" is the default.)
  • ReadOnly: Can be deleted. Cannot be 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.

Type:ScopedItemOptions
Accepted values:None, ReadOnly, Constant, Private, AllScope, Unspecified
Position:Named
Default value:None
Required:False
Accept pipeline input:False
Accept wildcard characters:False

-PassThru

Returns an object representing the new variable. By default, this cmdlet does not generate any output.

Type:SwitchParameter
Position:Named
Default value:False
Required:False
Accept pipeline input:False
Accept wildcard characters:False

-Scope

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

  • Global
  • Local
  • Script
  • Private
  • 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.

For more information, see about_Scopes.

Type:String
Position:Named
Default value:Local
Required:False
Accept pipeline input:False
Accept wildcard characters:False

-Value

Specifies the value of the variable.

Type:Object
Position:1
Default value:None
Required:False
Accept pipeline input:True
Accept wildcard characters:False

-Visibility

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.

Valid values 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.

Type:SessionStateEntryVisibility
Accepted values:Public, Private
Position:Named
Default value:Public
Required:False
Accept pipeline input:False
Accept wildcard characters:False

-WhatIf

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

Type:SwitchParameter
Aliases:wi
Position:Named
Default value:False
Required:False
Accept pipeline input:False
Accept wildcard characters:False

Inputs

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.