What's the standard header in PowerShell scripts (documentation)?

Question

Can anyone tell me what the "standard header" that I see in a lot of PowerShell scripts is all about? I have been unable to find any explanation so far.
Here's a snippet:
<#
.SYNOPSIS
Counts the Grateful Dead shows in my archives
.DESCRIPTION
This script looks at my GD archive, and uses folder names to
determine show type (aud, sbd, etc), and checks to see what
shows have checked MD5s
.NOTES
File Name : count-gdshows.ps1
Author : Thomas Lee - [email protected]
Requires : PowerShell V2 CTP3
.LINK

Answer 1

The help data can be used inside a function body or in a script. A script is not much different than a function, actually you can think of it as a function *without* a name, the name is the script name. You can a function like:
function foo
<# 
.SYNOPSIS 
    Counts the Grateful Dead shows in my archives
#>
   param($a,$b)
   $a+$b
And execute it like:
foo -a 3  -b 4
or write the function body in a script file called foo.ps1 :
## foo.ps1 ##
<# 
.SYNOPSIS 
    Counts the Grateful Dead shows in my archives
#>
   param($a,$b)
   $a+$b
and execute it like so:
.\foo.ps1 -a 3 -b 4
they give the same output. Windows 7 is goiung to RTM soon and as you probably know PowerShell v2 ships with it, so you can switch to v2 in the very near future. I'm working with v2 since the CTP versions (on my production machine) and it is working very good, lots of new exiting stuff!
As for functions vs scripts... it depends. On my personal machine I save my functions in various ways. I categorize them and save each bunch in a seperate script file (i.e. utilities.ps1, exchange.ps1, ad.ps1 etc). Some files I use more on a regular basis so I dot-source them in my profile, other scripts I load when I need. v2 introduced a module concept so the next evolution of my script files will turn into modules.  I also implement some functions in ps1xml files, these are used to extend objects , via PowerShells' Extended Type System (ETS), you can find an example on my blog (http://blogs.microsoft.co.il/blogs/scriptfanatic/archive/2009/05/31/getting-certificates-expiration.aspx).
Shay Levy [MVP]
http://blogs.microsoft.co.il/blogs/ScriptFanatic
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