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Set-Variable

Updated: April 21, 2010

Applies To: Windows PowerShell 2.0

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>] [-Description <string>] [-Exclude <string[]>] [-Force] [-Include <string[]>] [-Option {<None> | <ReadOnly> | <Constant> | <Private> | <AllScope>}] [-PassThru] [-Scope <string>] [-Visibility {<Public> | <Private>}] [-Confirm] [-WhatIf] [<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.

Parameters

-Description <string>

Specifies the description of the variable.

 

Required?

false

Position?

named

Default Value

Accept Pipeline Input?

false

Accept Wildcard Characters?

false

-Exclude <string[]>

Omits the specified items. The value of this parameter qualifies the Path parameter. Enter a path element or pattern, such as "*.txt". Wildcards are permitted.

 

Required?

false

Position?

named

Default Value

Accept Pipeline Input?

false

Accept Wildcard Characters?

false

-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.

 

Required?

false

Position?

named

Default Value

Accept Pipeline Input?

false

Accept Wildcard Characters?

false

-Include <string[]>

Changes only the specified items. The value of this parameter qualifies the Name parameter. Enter a name or name pattern, such as "c*". Wildcards are permitted.

 

Required?

false

Position?

named

Default Value

Accept Pipeline Input?

false

Accept Wildcard Characters?

false

-Name <string[]>

Specifies the variable name.

 

Required?

true

Position?

1

Default Value

Accept Pipeline Input?

true (ByPropertyName)

Accept Wildcard Characters?

false

-Option <ScopedItemOptions>

Sets 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 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".

 

Required?

false

Position?

named

Default Value

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.

 

Required?

false

Position?

named

Default Value

Accept Pipeline Input?

false

Accept Wildcard Characters?

false

-Scope <string>

Determines the scope of the variable. Valid values are "Global", "Local", or "Script", or 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.

 

Required?

false

Position?

named

Default Value

Accept Pipeline Input?

false

Accept Wildcard Characters?

false

-Value <Object>

Specifies the value of the variable.

 

Required?

false

Position?

2

Default Value

Accept Pipeline Input?

true (ByValue, ByPropertyName)

Accept Wildcard Characters?

false

-Visibility <SessionStateEntryVisibility>

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.

 

Required?

false

Position?

named

Default Value

Public

Accept Pipeline Input?

false

Accept Wildcard Characters?

false

-Confirm

Prompts you for confirmation before executing the command.

 

Required?

false

Position?

named

Default Value

Accept Pipeline Input?

false

Accept Wildcard Characters?

false

-WhatIf

Describes what would happen if you executed the command without actually executing the command.

 

Required?

false

Position?

named

Default Value

Accept Pipeline Input?

false

Accept Wildcard Characters?

false

<CommonParameters>

This command supports the common parameters: Verbose, Debug, ErrorAction, ErrorVariable, OutBuffer, OutVariable, WarningAction, and WarningVariable. For more information, see about_CommonParameters.

Inputs and Outputs

The input type is the type of the objects that you can pipe to the cmdlet. The return type is the type of the objects that the cmdlet returns.

 

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.

Example 1

C:\PS>set-variable -name desc -value "A description"

C:\PS>get-variable -name desc

Description
-----------
These commands set the value of the "desc" variable to "A description", and then get the value of the variable.







Example 2

C:\PS>set-variable -name processes -value (Get-Process) -option constant -scope global -description "All processes" -passthru | format-list -property *

Description
-----------
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

C:\PS># set-variable -name counter -visibility private

C:\PS> new-variable -name counter -visibility public -value 26

C:\PS> $counter
26

C:\PS> get-variable c*

Name Value
---- -----
Culture en-US
ConsoleFileName
ConfirmPreference High
CommandLineParameters {}
Counter 26

C:\PS> set-variable -name counter -visibility private

C:\PS> get-variable c*

Name Value
---- -----
Culture en-US
ConsoleFileName
ConfirmPreference High
CommandLineParameters {}

C:\PS> $counter
"Cannot access the variable '$counter' because it is a private variable"

C:\PS> .\use-counter.ps1
Commands completed successfully.

Description
-----------
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.







See Also

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