{"id":10811,"date":"2006-04-25T12:17:59","date_gmt":"2006-04-25T12:17:59","guid":{"rendered":"https:\/\/blogs.msdn.microsoft.com\/powershell\/2006\/04\/25\/a-bit-about-scriptblocks\/"},"modified":"2019-02-18T13:25:03","modified_gmt":"2019-02-18T20:25:03","slug":"a-bit-about-scriptblocks","status":"publish","type":"post","link":"https:\/\/devblogs.microsoft.com\/powershell\/a-bit-about-scriptblocks\/","title":{"rendered":"A bit about Scriptblocks"},"content":{"rendered":"

When scripting with MSH one of the most useful things to know about are scriptblocks (lambda functions).  <\/span>Scriptblocks are compiled bits of MSH script which you can pass around and invoke whenever you feel like it.  <\/span>They turn out to be so useful that if you look at the cmdlets you\u2019ll find a few that take scriptblocks (foreach-object, where-object, time-expression, select-object, format-table ).  <\/span>So how do we create scriptblocks?  <\/span>Well, if you\u2019ve ever used foreach-object you already know how to do it.  <\/span>Simply write some MSH inside { }  <\/span>and you\u2019re done.  <\/span>You can invoke them using & or \u201c.\u201d for dot sourcing.  <\/span>Pipeline input will be in $input and your arguments will be in $args.  <\/span>Here\u2019s a quick demo: <\/span><\/p>\n

 <\/span><\/p>\n

MSH>$script = { write-host “The scriptblock has been invoked.”<\/span>; write-host “Pipe: $input”<\/span>; write-host “Args: $args”<\/span> }
MSH>1<\/span>,2<\/span>,3<\/span> | & $script 4<\/span> 5<\/span> 6<\/span>
The scriptblock has been invoked.
Pipe: 1<\/span> 2<\/span> 3<\/span>
Args: 4<\/span> 5<\/span> 6<\/span>
MSH>function<\/span> InvokeTheScript([scriptblock]$myScript) { & $myScript }
MSH>InvokeTheScript $script
The scriptblock has been invoked.
Pipe:
Args:
MSH>InvokeTheScript { 1<\/span> + 1<\/span> }
2<\/span>
MSH>1<\/span>,2<\/span> | foreach<\/span>–object<\/span> $script
The scriptblock has been invoked.
Pipe: 1<\/span>
Args:
The scriptblock has been invoked.
Pipe: 2<\/span>
Args:<\/font><\/font><\/span> <\/span><\/p>\n

Funny how that function declaration has something resembling a scriptblock after the parameters huh?  <\/span>Well\u2026 if you were to look at the function provider you\u2019d quickly find out that it is indeed a scriptblock.  <\/span>A named scriptblock, but a scriptblock nonetheless.  <\/span><\/span><\/p>\n

 <\/span><\/p>\n

MSH>get-item function<\/span>:\\InvokeTheScript | get-member<\/p>\n

   TypeName: System.Management.Automation.FunctionInfo<\/p>\n

Name            MemberType   Definition
—-            ———-   ———-
Equals          Method       System.Boolean Equals(Object<\/span> obj)
get_CommandType Method       System.Management.Automation.CommandTypes get_CommandType()
get_Definition  Method       System.String<\/span> get_Definition()
get_Name        Method       System.String<\/span> get_Name()
get_Options     Method       System.Management.Automation.ScopedItemOptions get_Options()
get_ScriptBlock Method       System.Management.Automation.ScriptBlock get_ScriptBlock()
GetHashCode     Method       System.Int32 GetHashCode()
GetType         Method       System.Type GetType()
set_Options     Method       System.Void<\/span> set_Options(ScopedItemOptions value)
ToString        Method       System.String<\/span> ToString()
MshDrive        NoteProperty System.Management.Automation.DriveInfo MshDrive=Function<\/span>
MshIsContainer  NoteProperty System.Boolean MshIsContainer=False
MshPath         NoteProperty System.String<\/span> MshPath=Microsoft.Management.Automation.Core\\Function<\/span>::InvokeTheScript
MshProvider     NoteProperty System.Management.Automation.ProviderInfo MshProvider=Microsoft.Management.Automation.C…
CommandType     Property     System.Management.Automation.CommandTypes CommandType {get;}
Definition      Property     System.String<\/span> Definition {get;}
Name            Property     System.String<\/span> Name {get;}
Options         Property     System.Management.Automation.ScopedItemOptions Options {get;set;}
ScriptBlock     Property     System.Management.Automation.ScriptBlock ScriptBlock {get;}<\/p>\n

MSH>(get-item function<\/span>:\\InvokeTheScript).ScriptBlock
param([scriptblock]$myScript) & $myScript
<\/font><\/span><\/p>\n

 <\/span> <\/span><\/p>\n

I\u2019d give you some really good examples of scriptblock usage but I don\u2019t know any.<\/span> JK, of course.  <\/span>Actually, a long time ago one of our PMs used scriptblocks in such an excellent way so I\u2019ll just point you guys to his post about it.<\/span><\/p>\n

 <\/span><\/p>\n

http:\/\/www.proudlyserving.com\/archives\/2005\/07\/monad_and_rss_p_2.html<\/a><\/span><\/p>\n

– Marcel<\/p>\n

[Edit: Monad has now been renamed to Windows PowerShell. This script or discussion may require slight adjustments before it applies directly to newer builds.<\/i>]<\/p>\n","protected":false},"excerpt":{"rendered":"

When scripting with MSH one of the most useful things to know about are scriptblocks (lambda functions).  Scriptblocks are compiled bits of MSH script which you can pass around and invoke whenever you feel like it.  They turn out to be so useful that if you look at the cmdlets you\u2019ll find a few that […]<\/p>\n","protected":false},"author":600,"featured_media":13641,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1],"tags":[],"class_list":["post-10811","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-powershell"],"acf":[],"blog_post_summary":"

When scripting with MSH one of the most useful things to know about are scriptblocks (lambda functions).  Scriptblocks are compiled bits of MSH script which you can pass around and invoke whenever you feel like it.  They turn out to be so useful that if you look at the cmdlets you\u2019ll find a few that […]<\/p>\n","_links":{"self":[{"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/posts\/10811","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/users\/600"}],"replies":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/comments?post=10811"}],"version-history":[{"count":0,"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/posts\/10811\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/media\/13641"}],"wp:attachment":[{"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/media?parent=10811"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/categories?post=10811"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/tags?post=10811"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}