Powershell and Paradigms of VB

I have talked about experiences from long ago in other posts and, here’s another. When I was at University, one of my tutors, Dr Brian Lings, used the word “Paradigm” in a lecture. And we all went “WHAT !” and went running to dictionaries to find out what he meant. He actually used it in the context of looking at something written in one language but actually having the way-of-doing-things that you’d see in another.

I was reminded of this when I was asked to help with some PowerShell scripts for the OCS resource kit. I was sent a script which looked like this.

# Get all SIP domains

$SIPDomains = Get-WmiObject -class MSFT_SIPDomainData

# For every SIP domain in environment write SIP domain info to standard output

foreach ($SIPDomain in $SIPDomains) {
    write-host "*******************************"
    write-host SIP domain: $SIPDomain.Address
    write-host "*******************************"
    write-host \`t Default Domain : $SIPDomain.DefaultDomain
    write-host \`t Authoritative : $SIPDomain.Authoritative
}

Getting the WMI Object class MSFT_SIPDOMAINdata gives a collection of Objects: one per domain. So, we store that collection in a variable and use a foreach loop to go through each object and write its properties to the screen. Simple.

Well… except for that fact that Write-Host (despite the comment) isn’t sending to “Standard Output” and can’t be redirected to a file. We can’t use
     Get-SIPDomains > domains.txt
But even fixing that, this isn’t PowerShell “style” - though I’m still learning what that is, exactly. It’s written like we’d write VB.

Using LISP at university meant that grew to like one function to feed into the next, so piping functions into each other seems natural and PowerShell gives me cmdlets like Format-Table to take the results of Get-WMIobject and reduce the For loop to one line.

Get-WmiObject -class MSFT_SIPDomainData | Format-Table Address, Authoritative, DefaultDomain.

I’m beginning to see why they named it POWER shell; one of the other scripts I need to write for the OCS resource kit needs to get information from the event log. I was presently surprised to find PowerShell has a Get-EventLog cmdlet. With Where-Object to filter the events I can do this in one line.

This post orignally appeared on my technet blog in 2007

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