PowerShell is a powerful cmdlet-based scripting language that can be used to manage and automate tasks in your day-to-day work. Here are five cmdlets that can help you get started with PowerShell:
- Get-Command -Name “Get-ChildItem” -Path “C:\Windows\system32\drivers\etc”
- Set-Command -Name “Set-ItemProperty” -Value “value1=value2”
- Get-ChildItem -Path “C:\Windows\system32\drivers\etc” | Out-File C:\Windows\system32\drivers\etc.txt
- New-Object System.IO.FileStream(“C:\Windows\system32\drivers\etc”,“Open”) 5. Set-Location C:\Windows
PowerShell is quickly becoming the preferred scripting language and CLI of Power Users as well as IT Pros. It’s well worth learning a few commands to get you started, so we’ve got 5 useful cmdlets for you to learn today.
Get-Command
The Get-Command is one of the most useful cmdlets in the whole of PowerShell, as it will help you getting to grips with PowerShell by letting you search for certain cmdlets. Using Get-Command on its own is admittedly not very useful as its just going to spit out every command that PowerShell has.
But from this we can see that that objects that PowerShell outputs have both a Name and a ModuleName property. Using this information we can fine grain our search, by searching for cmdlets that contain certain terms. For example if I wanted to find all cmdlets that contain the word “IP”, I could do this:
As you can see we still get quite a few results, our next option is to search within a specific module. In our case i will choose the NetTCPIP module.
Get-Help
Once you have found the cmdlet you are looking for using Get-Command, you are going to want to know the syntax and how you can use that specific cmdlet. This is where Get-Help comes in, if you have ever used the command line in Windows you probably did something like this:
Well that doesn’t work in PowerShell, this is because in PowerShell a space is used to separate a command from its parameters. So instead we use Get-Help and pass a cmdlets name to Get-Help as a parameter.
Get-Member
Get-Member allows us to get information about the objects that a cmdlets returns. The catch with get-member, is that it relies on PowerShell’s pipeline feature, to demonstrate this, we will can use the Get-Process cmdlet.
As you can see PowerShell’s output shows us some of the properties, which you can see at the top of each column. The first problem is that, while those are the properties you might be looking for most of the time, there are still more of them. The second problem is that it doesn’t show any methods that we are able to call on the object. To see the methods and properties we can pipe our output to Get-Member, like so:
While it may mean nothing to you right now, you will sooner or later need to use Get-Member, and the sooner you learn to use it the better. As an example, using the information from the output we could do something like:
That script will launch notepad, it then assigns output of “Get-Process –Name notepad” to the $NotepadProc variable, then we call the WaitForExit method on $NotepadProc which causes the script to pause until you close notepad, once you have closed notepad then the calculator will launch.
$_(Current Pipeline Object)
While not exactly a cmdlet, it is one of the most used special variables in PowerShell. The official name for $_ is “the current pipeline object” . It is used in script blocks, filters, the process clause of functions, where-object, foreach-object and switches. However it is easier to explain with an example, which brings us to our next and final cmdlet, Where-Object.
Where-Object
Where-Object does exactly what it sounds like, it selects an object based on whether it meets a certain criteria. This will bring together $_, and the properties we can see using Get-Member. To demonstrate this, we will pipe the output of Get-Process into the Where-Object cmdlet.
So what’s going on here you ask? Well the first thing we are doing is getting a list of processes on our computer and passing the output (using the | character) to our Where-Object cmdlet, which takes a script block as a parameter. The script block (defined by the curly braces) instructs the Where-Object cmdlets to only select objects where their name parameter is equal to “iexplore”, and so we only get a list of the IE instances that are running. That’s all there is to it, have fun!
