Running Scripts

Applies To: Virtual Machine Manager 2008, Virtual Machine Manager 2008 R2, Virtual Machine Manager 2008 R2 SP1

This topic explains how to enable scripting in Windows PowerShell, which script extensions are used in Windows PowerShell, and how to run a script.

When you start Windows PowerShell on a computer, the default security policy does not allow you to run scripts. The Windows PowerShell security policy for scripting is called an execution policy. The execution policy lets you determine whether scripts can run in your environment and whether they must include a digital signature. None of the execution policies in Windows PowerShell allow you to run a script by double-clicking its icon because that is a high-risk method of running a script.

The following execution policies govern scripting in Windows PowerShell:

• Restricted. Permits interactive commands only (no scripts). This is the default.

• AllSigned. Permits scripts, but requires a digital signature from a trusted publisher for all scripts and configuration files, including scripts that you write on the local computer.

• RemoteSigned. Permits scripts, but requires a digital signature from a trusted publisher for all scripts and configuration files that are downloaded from the Internet, including e-mail. A digital signature is not required for scripts that you create on the local computer.

• Unrestricted. Permits scripts, including unsigned scripts.

Because the default Windows PowerShell execution policy is Restricted, you cannot run Windows PowerShell scripts until you change to a less restrictive execution policy. The following table lists Windows PowerShell Help topics that explain what you need to know about Windows PowerShell execution policies and how to change your policy so that you can run scripts.

Three extensions are available for script files in Windows PowerShell, although most script files have the .ps1 extension.

When you run a Windows PowerShell script, you must always indicate the full path with the name of the script even if you are working in the directory in which the script is located. You can use the following methods to run a Windows PowerShell script:

• Use the dot and the backslash (.\) to indicate the local directory. For example:

  .\ <ScriptName>.ps1

• Specify the full path of the script. For example:

  C:\Scripts\<ScriptName>.ps1

• Specify the path of the script, but omit the extension. For example:

  C:\Scripts\<ScriptName>

• Use the Invoke-Expression cmdlet to run a script. For example:

  Invoke-Expression C:\Scripts\<ScriptName>.ps1

• Use double quotation marks for any paths that include spaces. For example:

  Invoke-Expression "C:\My Scripts\<ScriptName>.ps1"

• Use the ampersand to run a script. For example:

  & C:\Scripts\<ScriptName>.ps1