As I've been working with PowerShell more and more, I keep picking up small tidbits I'd like to share. Arguably, I'd have learned a lot of them much sooner if would've picked up a book or something, but I look at this as a language I'll just pick up over time and don't really want to dedicate the time to a book... at least not at this point. So, I've decided to start throwing out a few PowerShell tips. I'd like to do a tip of the day, but I don't know if I'll come up with that many. We'll see. For this first post, I guess I should give a very brief overview of what PowerShell is and a few of the basic concepts behind it.
PowerShell is Microsoft's command line replacement. If you've ever done any time on the command line -- yes, I phrase it that way on purpose -- then you know it can be a pain. Not only is it painful, like any "good" prison, it's very limiting... another prison-like attribute. Another aspect I believe PowerShell is trying to attack is Windows shell scripting with VBScript or a similar language. I've used VBScript a few times for UI automation and I have to say, it's not much better than the traditional command line. The bottom line is that PowerShell is a powerful scripting environment for Windows.
So here are the basics: cmdlets, aliases, functions, and the pipeline. Cmdlets are commands. Go figure. If you want to do something, it all comes down to the commands you have available to you. To get a list of commands, type Get-Command. From there, you can figure out what's possible. If you have any questions about how to use them, type Get-Help [cmdlet]. Aliases are exactly what they sound like, aliases for cmdlets. This is one of the great things about PowerShell because it allows people to adopt PowerShell much easier. For instance, dir and ls are both aliases for the Get-ChildItem cmdlet, which is great for DOS and Linux/Unix users, respectively. Notably, the parameters are still PowerShell parameters and not the same as what's in DOS or the *nix systems. Functions are like a gateway drug to true PowerShell productivity. Think of functions as small scripts -- once again, go figure. Lastly, the pipeline is a concept that one command, whether that be a cmdlet or function, can send its output to another command via the pipeline. This is done by using the pipe ("|") character. For instance, to sort a list of folder contents by size, you pipe the contents to one that will sort the items it receives: Get-ChildItem | Sort-Object Length. Pretty simple. The key here, and true power of PowerShell, is the fact that PowerShell acts on .NET objects. This is a first. All other command line environments are pure text and piping content from one command to another is simply sending text down the pipe. Being built on .NET, PowerShell gives us an unprecedented amount of control and flexibility in our scripting.
To give you an idea of Microsoft's dedication to PowerShell, there's an internal mandate that all system administration tools must be built on PowerShell by 2009. The latest Exchange, Active Directory, and System Center releases have already made the switch and SQL Server 2008 is well its way, too.
I'll leave the intro here. In coming posts, I'll dig a little deeper into new features that I find. I'd like this to ultimately turn out to be a developers' guide to PowerShell, but that's more lofty a goal than I'm ready to sign up for. We'll see how things progress.