How Does A PowerShell Function Work? – Let’s Find Out
by Soumava Goswami Technology 28 October 2023
In PowerShell, a function is a list of statements that consist of names that you assign to each function. Whenever you run a PowerShell function, you will need to type the name of the function. Once you run the function in the command prompt, the statements in the list will then run. However, the complexity of a function can be different depending on how complex your program is or how you want it to be.
In this article, you will learn about what a PowerShell function is and how it works in general in a Microsoft system. We will also discuss the syntax of a function in Windows PowerShell. Finally, we will also discuss the complexity of functions in PowerShell, based on what is a basic function and what is an advanced function. Hence, to learn more about such types of functions, read on through to the end of the article.
What Is A PowerShell Function?
According to Business.com, “A function in PowerShell is a grouping of code that has an optional input and output. It’s a way of collecting a bunch of code to perform one or many times by just pointing to it instead of duplicating that code repeatedly. For example, you can build functions to perform tasks such as syncing folders or managing IIS application pools.”
Basically, a PowerShell function lets you avoid duplicating codes when there are repeating elements in your script. This helps you to focus more on modularity and reusability while ensuring best practices while you are writing your programs.
Creating PowerShell functions on your script while you are writing codes can help you save a lot of time since you will not need to copy and paste the code every time. You can just run the function in the script at the necessary place. Functions are basically small building blocks of code that help you to avoid duplicate programs.
To take full advantage of Windows PowerShell, you will not need to write full scripts. If you want to test a function quickly, you will need to define it directly in the PowerShell console. This shall allow you to quickly prototype your script. You can also run ad hoc tasks on the PowerShell despite not quitting the console session.
How Does A PowerShell Function Work?
Based on the complexity of your code and a particular list of operations within your code, you can add your function. The PowerShell function is just a list of all the PowerShell statements, and you can assign the name of the function as per requirement. There are also some pre-available functions in Windows PowerShell.
If you want to run a function, all you need to do is type the name of the function. The statements in the list run after you have typed the function in the command prompt.
As already discussed, functions can be both simple and complex based on the requirements of the script. It can be a simple PowerShell function:
|function Get-PowerShellProcess |
The PowerShell function can also be a complex one like a cmdlet or an application. In cmdlet functions, there are parameters based on type named, positional, switch, or dynamic. You can also read functions from the command line or the PowerShell pipeline.
According to Microsoft.com, “Functions can return values that can be displayed, assigned to variables, or passed to other functions or cmdlets. You can also specify a return value using the ‘return’ keyword. The return keyword doesn’t affect or suppress other output returned from your function. However, the return keyword exits the function at that line.”
Syntax Of A PowerShell Function
The following are the major constituents of a PowerShell function:
- The keyword named ‘function’
- The scope of a function (optional)
- The name of the function (you can select it)
- Named parameters (optional)
- One or more PowerShell commands within braces
Types Of Functions In Powershell
A PowerShell function can be a basic function or an advanced function:
The basic functions in PowerShell are simple, and they do not have several built-in capabilities like advanced functions. You can create or declare a function by using the function statement and can create or declare an existing function along with a set of curly braces. For example,
Write-Host ‘I am a coder!’
You can then invoke the function in the command prompt this way:
PS > MyCoder
The output then will come as –
I am a coder!
You will need basic functions in only some cases. To write real-life programs that are complex, you will need to create advanced PowerShell functions. These functions include all the functionality of basic functions, as well as various in-built functions in the PowerShell.
According to ATA Learning, “PowerShell functions can have any number of parameters. When you create your own functions, you’ll have the option to include parameters and decide how those parameters work. The parameters can be mandatory or optional, and they can either accept anything or be forced to accept one of a limited list of possible arguments.”
Basically, an advanced function can have many common parameters that are automatically added to the function.
Here is the general syntax of an advanced PowerShell function:
Whether a given function is a PowerShell function or not, it allows you to compartmentalize your script into Smaller building blocks of codes. With the help of functions, you can not only break down your code into discrete and manageable chunks but can also easily create readable codes and test them easily.
If you want to use PowerShell functions in your code, start by checking some of your old scripts, and add the function wherever required. The best way to do it is by looking for patterns in the code and building your function based on those patterns. Do you have any information to add? Share your ideas with us in the comments section below.