about_Requires

TOPIC
	about_Requires

SHORT DESCRIPTION
	Prevents a script from running by requiring the specified snap-ins and 
	version.

LONG DESCRIPTION
	The #Requires statement prevents a script from running unless the Windows 
	PowerShell version, snap-in, and snap-in version prerequisites are met. If 
	the prerequisites are not met, Windows PowerShell does not run the script. 

	You can use #Requires statements in any script. You cannot use them in 
	functions, cmdlets, or snap-ins. 


  Syntax 

	Use the following syntax to specify the snap-in and the version of the 
	snap-in that you want to require: 

		#requires –PsSnapIn <PsSnapIn> [-Version <N>[.<n>]]


	Use the following syntax to specify the minimum version of 
	Windows PowerShell that you want to require: 

		#requires -Version <N>[.<n>]


	Use the following syntax to specify the shell that you want to require: 

		#requires –ShellId <ShellId>


  Rules for Use 

	- The #Requires statement must be the first item on a line in a script.

	- A script can include more than one #Requires statement. 

	- The #Requires statements can appear on any line in a script.


  Examples

	The following statement requires the Microsoft.PowerShell.Security 
	snap-in:

		#requires –PsSnapIn Microsoft.PowerShell.Security


	If the Microsoft.PowerShell.Security snap-in is not loaded, the script 
	does not run, and Windows PowerShell displays the following error 
	message: 

		"The script '<script-name>' cannot be run because the following 
		Windows PowerShell snap-ins that are specified by its "#requires" 
		statements are missing: Microsoft.PowerShell.Security." 


	The following statement requires the Windows PowerShell 2.0 version or
	any later version of the Microsoft.PowerShell.Security snap-in:

		#requires –PsSnapIn Microsoft.PowerShell.Security –Version 2


	The following statement requires Windows PowerShell 2.0 or a later 
	version:

		#requires –Version 2.0


	The following script has two #Requires statements. The requirements 
	specified in both statements must be met. Otherwise, the script will not
	run. Each #Requires statement must be the first item on a line:

		#requires –PsSnapIn Microsoft.PowerShell.Security –Version 2
		Get-WMIObject WIN32_LogicalDisk | out-file K:\status\DiskStatus.txt
		#requires –Version 2


	The following #Requires statement prevents a script from running if the 
	specified shell ID does not match the current shell ID. The current 
	shell ID is stored in the $ShellId variable:

		#requires –ShellId MyLocalShell


SEE ALSO
	about_Automatic_Variables 
	about_Language_Keywords
	about_PSSnapins
	get-PSSnapin