Showing the current OS

Get-ComputerInfo

Commands

File System Commands

Showing the path of the current directory

Get-Location

Showing the content of the current directory

Get-ChildItem

The same recursively and with filter capability

The following command lists all files files matching the filter criteria inside the folder cypress recursively:

Get-ChildItem -Path "cypress" -Filter *cy.ts -Recurse

The same for the current path:

Get-ChildItem -Filter *cy.ts -Recurse

Other commands

Creating a new GUID

There are different ways to easily create a new GUID using PowerShell, here are two different ways to achieve it:

First example:

[guid]::NewGuid()

Second example:

New-Guid

Environment variables

Showing all environment variables

To show all environment variables in PowerShell, you can use the Get-ChildItem command with the Env: option as the following example shows:

Get-ChildItem Env:

Functions

The following example shows how you can declare and use a custom function in PowerShell:

function Get-Version {
    $PSVersionTable.PSVersion
} 

Get-Version

You can also

Function with parameters

The following example shows a simple function CalculateY which is called and passed the value 10 to its variable X, which then calculates the square of that value and prints it out:

function CalculateY{
    param(
       [Int]$X
    )

    Write-Output "$($X * $X)"
}

CalculateY -X 10 

You can have the same with a slightly different syntax as follows:

function CalculateY($X){

    Write-Output "$($X * $X)"
}

CalculateY -X 10

Return value

The following example explains how the function can return a value and how that value can be used to do something with it, for example writing it into output:

function GetArray
{
    $array = 1,2,3,4
    return $array
}

$a = GetArray
Write-Output $a

This will produce the following output:

1 2 3 4

But in fact, the return keyword is not even necessary, you basically get the same result with the following code without the return keyword:

function GetArray
{
    $array = 1,2,3,4
    $array
}

$a = GetArray
Write-Output $a 

Unexpected behavior with using Write-Output inside a function

Be aware that using Write-Output inside a function might cause unexpected behavior because Write-Output write to the same stream where the return value is written. The following example shows how having Write-Output inside a function can change your return value in an unexpected way:

Script:

function GetArray
{
    $array = 1,2,3,4
    Write-Output "xyz"
    return $array
}

$a = GetArray
Write-Output $a
Write-Output $a 

Output:

xyz 1 2 3 4 xyz 1 2 3 4

As you can see we call the function only once, but xyz is written out to output twice. This means that Write-Output directly effects the return value, meaning that the string xyz becomes part of the return value.

Here you can read more about this problem:

https://community.spiceworks.com/topic/2189940-powershell-write-output-in-function-with-return-value

PowerShell ISE

Commenting out

Commenting out a line:

Commenting out a block of lines: