Powershell How-To - Part 1

Introduction

I was excited hear about powershell feature in SQL server 2008. Initially, it was not clear to me what it was, yet, I was enthused about learning something new. I imagined power shell would involve something in the command line. What happens after that was a complete mystery to me. Anyways, I managed to spend some extra time to learn about the powershell technology. I am going to split this article into multiple series. In the 1st part, I will cover how to work with variables and various helpful commandlets. The examples in this article assumes SQL server 2008, and windows powershell 1.0 is present. 

Background

Powershell is an extended shell that allows us to manipulate objects and do various scripting tasks. It takes the adavantage of .NET. We will often run into CmdLet in powershell. A commandlet is a .NET object that exposes functionalities for us. For example, there is a cmdlet called "New-Variable" which can be used to declare variables. 

Using the code

PS SQLSERVER:\> get-alias

CommandType     Name            Definition
-----------     ----            ----------
Alias           ac              Add-Content
Alias           asnp            Add-PSSnapin
Alias           clc             Clear-Content 

When I started working with powershell, I struggled to find documentation on cmdlet. I looked in books online and it did not have much at that time. Only some references were there related to cmd-lets. Anyways, there is no need to despair. A cmdlet called "Get-Help" that can help you pull cmdlet related documentation from the command line. You need to supply the name of the cmdlet as the argument. Other useful arguments available for most cmdlets include "-detailed", "-full". Those flags allows you to bring additional information on the parameter. Amongst the, the "-full" flag is the most comprehensive. Also, if you type in "Get-Help *" then you can see a list of all available help topics. Powershell documentation reminded me of the manpages in unix computer and the RTM mantra.

Strings, variables, objects:

Declaring and working with variables is very simple. It can be achieved via cmdlets such as "New-Variable", "Set-Variable". Also, we can declare it like one would do it in scripting languages like perl, php.

PS SQLSERVER:\> $rnd = New-Object "Random"
PS SQLSERVER:\> $rnd.Next()
778277127
PS SQLSERVER:\> $str = "Me"
PS SQLSERVER:\> $i = 1

PS SQLSERVER:\> $i.GetType()

IsPublic IsSerial Name            BaseType
-------- -------- ----            --------
True     True     Int32           System.ValueType

Points of Interest

I presented the article materials at the SQL Server user group several months ago. I learned from one of the MS employee that powershell 2.0 was coming out. The new version is expected to cover remoting issues.

History

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