PowerShell Basics: Finding Your Way in the PowerShell Console

For me, one of the most important features of PowerShell is the ability to find all the answers you need in the shell. From the early days, PowerShell has included commands for finding cmdlets and functions within the shell including Get-Command. Get-Command is one of the three most well-known PowerShell commands, Get-Help and Get-Member being the other two. This post will be an exploration of using Get-Command and Get-Help. You can get information on Get-Member in this post.

Let’s start with Get-Command. Let’s say you want to see everything installed in your PowerShell console. That’s pretty easy. Type Get-Command and it produces a list of all the commands installed (functions, aliases, cmdlets).

This displays a few things of importance:

• CommandType is the type of command. These include alias, function, and cmdlet commands currently installed.
• Name is self-explanatory and is what you invoke to run the command.
• Version is the current version of the command you have installed.
• Source is the module that includes the command.

Let’s say you want to find just functions in the console. To do this, you simply add the -commandtype parameter with a value of function and it produces a list of functions only.

Venturing further down the rabbit whole, let’s see just the functions that start with the verb get- so we use the -name parameter with a value of Get-* and it produces the list we want.

You’ll notice I used a wildcard (*) in my value for name. It will get every command that begins with “Get-“. You can also see I’m following a systematic approach to find to what I’m looking for: Start with a wide net, and gradually reduce the size of the items caught. I use this approach with all queries for information with PowerShell.

So, let’s try something, I want to find a command that allows me to modify the firewall rules on a Windows host. Sure I could look on the internet, but that defeats the purpose of using tools in the box.

First, I’ll do a search using Get-Command looking for commands with “FireWall” in the -name parameter.

From the partial output, we received a variety of commands. This is because I used Wildcard (*) before and after firewall. This gives me the largest pool of commands containing “firewall” anywhere in the name of the command.

Reviewing the results, I see that there is a noun of NetFirewallRule. That sounds like it may be what I’m looking for so let’s try searching for -name *netfirewallrule, and we see what results.

Ah yes, now we are getting somewhere. I’ve managed to list all of the commands that work with NetFirewallRule. Ok. Which should I pick? Well, that can be tricky. We have a number of verbs here used with -NetFireWallRule. In this case, two verbs stick out: New and Set. Here’s the best way to remember these verbs and how they work:

• New ALWAYS should create net-new things. It should never be used to modify existing things. Use it to create new things.
• Set NEVER should create net-new things. Use it to modify things.

So Set-NetFirewallRule looks to be our winner. So, how do we use it? PowerShell Help to the rescue. PowerShell has a built-in help system to provide you all the information you need. It’s run by typing Get-Help <Command>.

Note: If you don’t see the output below, run Update-Help. Microsoft updates help files on a regular basis so you should make sure to run this occassionaly. You may need to run PowerShell as an admin for Update-Help to work. Also, all versions of PowerShell ship without the help files so they need to be updated upon first use.

And, it is the command we are looking for. The Synopsis and Description tell us what the command does (modifies the firewall rules).

To begin using the command, you can review the syntax for the parameters available with the command. For those new to PowerShell, this can be daunting so I’ll show you my favorite use of help with the -examples parameter

This handy parameter provides you examples, usually listed from simple to more complex, of how to work with the command. Often times, you’ll find a command that does some or all of the things you want. I like to copy the command from the help and use it as a base as I work through a command’s usage.

Let’s say example 1 that sets the remote IP address on a rule is what you want, but your not sure how to use the -remoteaddress parameter. For this, there are a couple of options.

First, you can run Get-Help <command> -Full to see all of the help content including detailed information on parameters. This will produce a ton of information in the console so try using help, a shortcut for get-help, instead. It still runs help but it adds the more functionality of paging each screen. This is great to use when you want all of the help information to review.

The next option is to get more granular and just search for the -RemoteAddress parameter by using -Parameter with help like this.

Now, that gets us the information we are looking for including a description of the parameter, acceptable formats for the parameter, and more. One important piece of information is the <...> value after the parameter name. This tells you the type of value the parameter accepts. In this case it’s a string value (numbers/letters/symbols). But it could have been a boolean or other value. This is important so you know what you can and can’t use in a parameter. This becomes super important later in your PowerShell journey when you begin using the pipeline.

So there you have it! A quick and easy approach for finding commands & how to use them. Use Get-Command and Get-Help whenever you need to do something in PowerShell. Add on Get-Member, and your on your way to becoming a PowerShell Guru!

If you want more information on each of these commands, check out the docs below:

Get-Command

Get-Help