about_CommonParameters

TOPIC
	about_CommonParameters

SHORT DESCRIPTION
	Describes the parameters that can be used with any cmdlet.


LONG DESCRIPTION
	The common parameters are a set of cmdlet parameters that you can
	use with any cmdlet. They are implemented by Windows PowerShell, not
	by the cmdlet developer, and they are automatically available to any
	cmdlet.


	You can use the common parameters with any cmdlet, but they might
	not have an effect on all cmdlets. For example, if a cmdlet does not
	generate any verbose output, using the Verbose common parameter
	has no effect.


	Several common parameters override system defaults or preferences
	that you set by using the Windows PowerShell preference variables. Unlike
	the preference variables, the common parameters affect only the commands
	in which they are used.
 

	In addition to the common parameters, many cmdlets offer the WhatIf and
	Confirm risk mitigation parameters. Cmdlets that involve risk to the system
	or to user data usually offer these parameters.


	The common parameters are:


	 -Verbose
	 -Debug
	 -WarningAction
	 -WarningVariable
	 -ErrorAction
	 -ErrorVariable
	 -OutVariable
	 -OutBuffer   

 
	The risk mitigation parameters are:


	 -WhatIf
	 -Confirm


	For more information about preference variables, type:

  
	 help about_preference_variables


  Common Parameter Descriptions	 

	-Verbose[:{$true | $false}]

		Displays detailed information about the operation performed by the
		command. This information resembles the information in a trace or in
		a transaction log. This parameter works only when the command generates
		a verbose message. For example, this parameter works when a command
		contains the Write-Verbose cmdlet.
	
		The Verbose parameter overrides the value of the $VerbosePreference
		variable for the current command. Because the default value of the
		$VerbosePreference variable is SilentlyContinue, verbose messages
		are not displayed by default.

		Valid values:

			$true (-Verbose:$true) has the same effect as -Verbose.

			$false (-Verbose:$false) suppresses the display of verbose
			messages. Use this parameter when the value of $VerbosePreference
			is not SilentlyContinue (the default). 



	-Debug[:{$true | $false}]

		Displays programmer-level detail about the operation performed by the
		command. This parameter works only when the command generates
		a debugging message. For example, this parameter works when a command
		contains the Write-Debug cmdlet.

		The Debug parameter overrides the value of the $DebugPreference
		variable for the current command. Because the default value of the
		$DebugPreference variable is SilentlyContinue, debugging messages
		are not displayed by default.
	 
		Valid values:

			$true (-Debug:$true). Has the same effect as -Debug.

			$false (-Debug:$false). Suppresses the display of debugging
			messages when the value of the $DebugPreference is not
			SilentlyContinue (the default). 



	-WarningAction[:{SilentlyContinue | Continue | Inquire | Stop}]   

		Determines how the cmdlet responds to a warning from the command.
		"Continue" is the default value. This parameter works only
		when the command generates a warning message. For example, this
		parameter works when a command contains the Write-Warning cmdlet.

		The WarningAction parameter overrides the value of the 
		$WarningPreference variable for the current command. Because the
		default value of the $WarningPreference variable is Continue, 
		warnings are displayed and execution continues unless you use the
		WarningAction parameter. 

		 Valid Values:

			SilentlyContinue. Suppresses the warning message and continues
			executing the command.

			Continue. Displays the warning message and continues executing
			the command. "Continue" is the default value.
 
			Inquire. Displays the warning message and prompts you for 
			confirmation before continuing execution. This value is rarely
			used.

			Stop. Displays the warning message and stops executing the
			command.



	-WarningVariable [+]<variable-name>

		Stores warnings about the command in the specified variable.

		To append the warnings to the variable content, instead of replacing
		any warnings that might already be stored there, type a plus sign (+)
		before the variable name. 

		For example, the following command creates the $a variable and then
		stores any warnings in it:

			get-process -id 6 -WarningVariable a   

		The following command adds any warnings to the $a variable:

			get-process -id 2 -WarningVariable +a  

		The following command displays the contents of $a:

			$a									 

		You can use this parameter to create a variable that contains only 
		warnings from specific commands. You can use array notation, such as
		$a[0] or $warning[1,2] to refer to specific warnings stored in the
		variable.


	-ErrorAction[:{SilentlyContinue | Continue | Inquire | Stop)]   

		Determines how the cmdlet responds to a non-terminating error
		from the command. This parameter works only when the command generates
		a debugging message. For example, this parameters works when a command
		contains the Write-Error cmdlet.

		The ErrorAction parameter overrides the value of the 
		$ErrorActionPreference variable for the current command. 
		Because the default value of the $ErrorActionPreference variable
		is Continue, error messages are displayed and execution continues
		unless you use the ErrorAction parameter. 

		The ErrorAction parameter has no effect on terminating errors (such as
		missing data, parameters that are not valid, or insufficient 
		permissions) that prevent a command from completing successfully.

		Valid values:

			SilentlyContinue. Suppresses the error message and continues
			executing the command.

			Continue. Displays the error message and continues executing
			the command. "Continue" is the default value.
 
			Inquire. Displays the error message and prompts you for 
			confirmation before continuing execution. This value is rarely
			used.

			Stop. Displays the error message and stops executing the
			command.

		
	-ErrorVariable [+]<variable-name>

		Stores error messages about the command in the specified variable
		and in the $Error automatic variable. For more information,
		type the following command:

			get-help about_automatic_variables

		By default, new error messages overwrite error messages that are 
		already stored in the variable. To append the error message to the
		variable content, type  a plus sign (+) before the variable name. 

		For example, the following command creates the $a variable and then
		stores any errors in it:

			get-process -id 6 -ErrorVariable a

		The following command adds any error messages to the $a variable:


			get-process -id 2 -ErrorVariable +a

		The following command displays the contents of $a:

			$a									 

		You can use this parameter to create a variable that contains only 
		error messages from specific commands. The $Error automatic
		variable contains error messages from all the commands in the session.
		You can use array notation, such as $a[0] or $error[1,2] to refer to 
		specific errors stored in the variables.


	-OutVariable [+]<variable-name>

		Stores output objects from the command in the specified variable and
		displays it at the command line.

		To add the output to the variable, instead of replacing any output 
		that might already be stored there, type a plus sign (+) before the
		variable name. 

		For example, the following command creates the $out variable and
		stores the process object in it:

			get-process powershell -OutVariable out	 

		The following command adds the process object to the $out variable:

			get-process iexplore -OutVariable +out 

		The following command displays the contents of the $out variable:

			$out									
  


	-OutBuffer <Int32>

		Determines the number of objects to accumulate in a buffer before
		any objects are sent through the pipeline. If you omit this parameter,
		objects are sent as they are generated. 
	
		This resource management parameter is designed for advanced users.
		When you use this parameter, Windows PowerShell does not call the 
		next cmdlet in the pipeline until the number of objects generated
		equals OutBuffer + 1. Thereafter, it sends all objects as they are
		generated.

	
  Risk Management Parameter Descriptions	
 
	-WhatIf[:{$true | $false}]
		Displays a message that describes the effect of the command, 
		instead of executing the command.

		The WhatIf parameter overrides the value of the $WhatIfPreference
		variable for the current command. Because the default value of the
		$WhatIfPreference variable is 0 (disabled), WhatIf behavior is not
		performed without the WhatIf parameter. For more information, type
		the following command:

			get-help about_preference_variables



		Valid values:

			$true (-WhatIf:$true). Has the same effect as -WhatIf.	
	
			$false (-WhatIf:$false). Suppresses the automatic WhatIf behavior
			that results when the value of the $WhatIfPreference variable 
			is 1. 

		For example, the following command uses the WhatIf parameter in a
		Remove-Item command:

			PS> remove-item date.csv -whatif

		Instead of removing the item, Windows PowerShell lists the operations
		it would perform and the items that would be affected. This command 
		produces the following output:

			What if: Performing operation "Remove File" on 
			Target "C:\ps-test\date.csv".

	
	-Confirm[:{$true | $false}]
		Prompts you for confirmation before executing the command.

		The Confirm parameter overrides the value of the $ConfirmPreference
		variable for the current command. The default value is High. For more
		information, type the following command:

			get-help about_preference_variables
	
		Valid values:

			$true (-WhatIf:$true). Has the same effect as -Confirm.	

			$false(-Confirm:$false). Suppresses automatic confirmation,
			which occurs when the value of $ConfirmPreference is less than
			or equal to the estimated risk of the cmdlet. 

		For example, the following command uses the Confirm parameter with a 
		Remove-Item command. Before removing the item, Windows PowerShell
		lists the operations it would perform and the items that would be
		affected, and asks for approval.

			PS C:\ps-test> remove-item tmp*.txt -confirm

		This command produces the following output:

			Confirm
			Are you sure you want to perform this action?
			Performing operation "Remove File" on Target " C:\ps-test\tmp1.txt
			[Y] Yes  [A] Yes to All  [N] No  [L] No to All  [S] Suspend  
			[?] Help (default is "Y"):


SEE ALSO
	about_Preference_Variables
	Write-Debug
	Write-Warning
	Write-Error
	Write-Verbose