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The first term I need to define is cmdlet.

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This is the basic PowerShell command.

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Think of the name as meaning little command, cmdlet.

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Cmdlets are written in a .NET language and compiled.

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Now,

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those details don't really matter to you other than realizing

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that these are essentially binary commands,

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so you can't see the source code.

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The most important aspect of a cmdlet is that it does one thing and

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writes one type of object to the PowerShell pipeline.

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Now,

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this is very similar to the Linux model where command line

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programs like grep and sed only do one thing,

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and then you join them together to make a single command statement.

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Now we don't have monolithic commands in PowerShell.

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We have commands that do specific things like get a service or stop a

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process or create a new Active Directory user account.

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A function isn't that much different than a cmdlet.

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In fact, it behaves just like a cmdlet.

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You, when you use it, really can't tell the difference.

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But one big difference is that functions are almost always

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written in PowerShell scripting language.

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This means you can look at the source code.

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Now you typically wouldn't change it,

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but because functions are typically a type of PowerShell script,

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you will eventually learn how to write your own.

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And functions, like cmdlets,

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are designed to do one thing and write one type of object to the pipeline.

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Yes, there are always exceptions,

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but that should be the model that you will follow.

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You'll also encounter the term script in PowerShell.

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Now scripting is the journal process of creating these types of commands.

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A PowerShell script is a text file with a PS1 file extension.

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The commands in the file are executed sequentially,

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just as if you had typed them manually at a PowerShell prompt.

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You can think of a PowerShell script as a fancy type of batch file.

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We use PowerShell scripts to define our functions,

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but more often we use scripts to run cmdlets and functions in

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some sort of structured or planned order.

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A good way to think of PowerShell scripts is as a controller or orchestrator.

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You can use a PowerShell script to automate tasks and steps.

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I often think of them as canned or recorded PowerShell sessions,

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so instead of interactively running a series of commands,

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I can put them in a PS1 file and execute the script.

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PowerShell scripts have a bit more flexibility and can do more than one thing,

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but you don't want to get too monolithic.

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There's plenty of PowerShell scripting content in the Pluralsight catalog.

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Technically, there is one more type of PowerShell command,

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and that is an alias. Although in reality an aliases just an

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alternate name for a PowerShell command,

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such as a cmdlet, function or script,

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they're often shorter and sometimes easier to use.

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So instead of typing the command Get‑Process,

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you could type a shorter alias like ps. In fact,

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one of the reasons we had aliases were to provide

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transitions from other shells and platforms.

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If you need to list files in a folder by don't know

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the actual PowerShell command yet, which,

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by the way, is Get‑ChildItem, you can use an alias like dir or ls.

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Although be aware that on Linux systems,

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many of the PowerShell aliases have been removed to avoid

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conflicting with the real native commands like ls or ps.

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The last definition I have for you is parameter.

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Now you'll hear this term a lot in PowerShell. This is something

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that applies to cmdlets, functions, and scripts.

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A parameter provides a way to customize the behavior of the command,

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such as specifying a certain path or group of services.

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Command line tools have always had parameters,

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sometimes they are referred to as switches.

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But don't hold on to that term as switch. In PowerShell,

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it means something entirely different, which you'll eventually learn.

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The important thing for you to know right now is that

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some parameters are positional,

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meaning you only have to type the value like the name of a service.

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Otherwise,

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all parameters in PowerShell follow a standard convention of a dash,

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then the parameter name, a space, and then the value.

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If you need to pass multiple values, like a group of computer names,

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those are separated by commas. As you work with PowerShell,

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you'll also see the parameter names are also kind of standardized.

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If you need to specify the parameter and pass the name of a computer,

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it's almost always going to be computer name.

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These standards make PowerShell commands easy to learn and use because you don't have to guess at they syntax.