TOPIC
    about_script_blocks

SHORT DESCRIPTION
    Defines what a script block is and explains how to use script blocks in
    the Windows PowerShell programming language.

LONG DESCRIPTION
    In the Windows PowerShell programming language, a script block is a
    collection of statements or expressions that can be used as a single unit.
    A script block can accept arguments and return values.

    Syntactically, a script block is a statement list in braces, as shown in
    the following syntax:

        {<statement list>}

    A script block returns the output of all the commands in the script block,
    either as a single object or as an array.

    Like Functions, a script block can include parameters. Use the Param
    keyword to assign named parameters, as shown in the following syntax:

        {
            param ([type]$parameter1 [,[type]$parameter2])
            <statement list>
        }

    In a script block, unlike a Function, you cannot specify parameters outside
    the braces.

    Like Functions, script blocks can include the DynamicParam, Begin, Process,
    and End keywords. For more information, see about_functions and
    about_functions_advanced.

Using Script Blocks

     A script block is an instance of a Microsoft .NET Framework type
     (System.Management.Automation.ScriptBlock). Commands can have script
     block parameter values. For example, the Invoke-Command cmdlet has a
     ScriptBlock parameter that takes a script block value, as shown in this
     example:

         C:\PS> Invoke-Command -scriptblock { Get-Process }
         Handles NPM(K)    PM(K)     WS(K) VM(M) CPU(s)     Id ProcessName
         ——- ——    —–     —– —– ——     — ———–
             999     28    39100     45020 262    15.88 1844 communicator
             721     28    32696     36536 222    20.84 4028 explorer
         . . .

     The script block that is used as a value can be more complicated, as
     shown in the following example:

         C:\PS> Invoke-Command -scriptblock { param ($uu = “Parameter”);
             “$uu assigned.” }
         Parameter assigned.

     The script block in the preceding example uses the Param keyword to
     create a parameter that has a default value. The following example uses
     the Args parameter of the Invoke-Command cmdlet to assign a different
     value to the parameter:

         C:\PS> Invoke-Command -scriptblock {param ($uu = “Parameter”);
             “$uu assigned.”} -args “Other value”
         Other value assigned.

     You can assign a script block to a Variable, as shown in the following
     example:

         C:\PS> $a = {param ($uu = “Parameter”); “$uu assigned.”}

     You can use the Variable with a cmdlet such as Invoke-Command, as shown
     in the following example:

         C:\PS> Invoke-Command -scriptblock $a -args “Other value”
         Other value assigned.

     You can run a script block that is assigned to a Variable by using the
     call operator (&), as shown in the following example:

         C:\PS> &$a
         Parameter assigned.

     You can also provide a parameter to the script block, as shown in the
     following example:

         C:\PS> &$a “Other value”
         Other value assigned.

     If you want to assign the value that is created by a script block to a
     Variable, use the call operator to run the script block directly, as
     shown in the following example:

         C:\PS> $a = &{param ($uu = “Parameter”); “$uu assigned.”}
         C:\PS> $a
         Parameter assigned.

     For more information about the call operator, see about_operators.

SEE ALSO
    about_functions
    about_functions_advanced
    about_operators