Write-Host

This cmdlet’s primary purpose is to provide output to the screen. It can also color text output by supplying the -ForegroundColor parameter as shown in Figure 1-6.

A screenshot of the Power Shell window depicts a code for write-host which is used to change the text color.

However, Write-Host can also be used to inform Intune whether something in the deployment template ran successfully or not. You will see later in the book how this works. In its Intune context, it is quite often used within a Try/Catch block.

Get-Location/Set-Location

Get-Location will get the current working location. For example, C:myFiles as shown in Figure 1-7.

A screenshot of the Power Shell window depicts a code to get-location.

You can recall the path for later use by assigning it to a variable. In PowerShell, variables are preceded with the dollar ($) symbol. The name of the variable can be almost anything you like.

Set-Location is its big brother (or sister). This command will set the working location to the one you have defined in the parameter -Path

Figure 1-8 shows that the working location was originally C:MyFiles and by using Set-Location the working location changed to C:Temp.

A screenshot of the windows Power Shell depicts a code to set-location.

Get-Process

Get-Process will get a list of all running processes on a local or remote computer. (See Figure 1-9)

A screenshot of the Power Shell window lists handles, N P M, P M, W S, C P U, I D, S I, and process name.

You may have an application that will not install if a certain process is running. In a deployment scenario, Get-Process can test that the process is running first, before piping (sending) it to Stop-Process.

Stop-Process

Stop-Process will stop all instances of a running process.

Say you had an application that would not install if Notepad was running; you could add a prerequisite in the deployment template (more on this later) to test for the running process and if found, stop it.

By default, Stop-Process will stop any process owned by the current user.

If the process is not owned by the current user and the command is not being run with administrative privileges, then an access denied message is displayed.

If the process is not owned by the current user but the command is run with administrative privileges then a prompt is displayed asking if you are sure you wish to perform the action, and then awaits a keypress to either confirm or deny the action; certainly not the desired outcome when deploying scripts. (See Figure 1-10)

A screenshot of an administrator, windows PowerShell depicts a code for stop-process.

To avoid this undesired confirmation prompt, and I’ve been building up to this moment since starting to write the chapter, you will need to use The Force!

Start-Process

Start-Process is an easy cmdlet to grasp because it simply starts a process on a local computer.

There’s a lot more to Start-Process than meets the eye though and you will be reading more about this cmdlet in a later chapter.

New-Item

New-Item creates a new item and can also set its value. The type of item it creates depends on the location. For instance, in the file system, it can create files and folders; however, in the registry, it will create registry keys and entries.

This cmdlet shines in deployments and is particularly useful for custom detection rules. (More of this later in the book.)

In this example, a text file is created named testfile.txt in the directory c:myfiles. Additionally, the text file has the text “This is a text string.” (See Figure 1-11)

A screenshot of the windows Power Shell depicts a code to create a new-item. The options for mode, last write time, and length name are provided.

New-ItemProperty

This cmdlet is mainly used for creating a new item and setting its value. It is typically used to create new registry values.

In the context of deploying applications, this is frequently used for custom detection scripts or simply manipulating the registry as part of a pre- or post-application deployment.

Get-Item

This cmdlet gets an item and is very flexible in what it can do. Frequently used in detection rules, it can effortlessly obtain a version number from an executable, which can then be used to compare against an expected value.

Figure 1-12 shows how to obtain the version number of snagit.exe.

A screenshot of the windows Power Shell depicts a code to get-item. The options in the code are product version, file version, and file name.

You will learn more about this cmdlet in a later chapter.

Copy-Item

Test-Path

This cmdlet is used to determine if a file or folder in a given path exists or not. If the path exists it returns true, if not it returns false.

Figure 1-13 demonstrates using Test-Path to determine if the file “A text document.txt” exists in C:Temp. The cmdlet returns true – the file exists!

Test-Path -Path "C: empA Text Document.txt"

A screenshot of the windows Power Shell depicts a code for test-path.

The more astute among you may have noticed that I paired the two cmdlets: Get-Location with Set-Location. I’ll hold my hands up; you caught me. Technically it’s eleven cmdlets but I wanted to use the whole The Ten Cmdlets heading thing as a play on words, so what’s a guy supposed to do?

While there are only a few cmdlets to learn, they should cover about 99% of any complex or odd deployment requests that come your way. For that edge-case 1% that lands on your table: you are now fully equipped on how to read the help for the cmdlets that you have yet to discover.

What About That Help?

PowerShell comes with many constructs that can help with scripting, for example, Do, While, and For loops or functions and advanced functions, variables, etc. So how do you look up help for these topics?

(See Figure 1-14)

A screenshot of the windows Power Shell lists name, and category module.

(See Figure 1-15)

A screenshot of the windows Power Shell depicts Booleans, converting from scalar types with examples provided.

Try/Catch/Finally

Try/Catch block is great for trapping potential errors and taking alternative action if an error is detected. It can be explained something like this: “Try and perform the following commands, but if it doesn’t work, catch the error and do this instead.”

In the following example code, it tries to do something with the word “error” in the try block, but as PowerShell does not know what this is it will generate an error.

Because an error was caused, the catch block takes effect, and a message is displayed to the user informing them that there was an error.

The optional Finally block will always run regardless of an error being produced or not.

If/Else

The If statement is used a great deal in scripting. It’s used in a manner akin to this: “If this condition is met then do this, otherwise (or else) do this instead.”

Note the “Else” is optional – you can use If by itself if that is all it takes to achieve your goal.

Here’s an example where you might use an If/Else: let’s say you wanted to copy files to a destination directory C:Destination but only if the destination directory already existed. If the destination directory did not exist, you would take some other action; perhaps create the directory first and then copy the file.

You know from studying the previous cmdlets that Test-Path will result in either true or false depending on if the specified path exists or not. In this scenario, it’s the perfect cmdlet to use with the If statement.

By default, If will recognize a true response on the condition between the brackets and execute the code to copy files without you having to explicitly state “if test-path returns true.”

However, if Test-Path returns false (the path does not exist), then the code in the else block will execute instead.

If you wanted to test for a false response you can use an exclamation mark. This reverses the evaluation: “If Test-Path returns false then do this, otherwise (else) do this.”