PowerShell Primer & Guide

What is PowerShell?

PowerShell is Microsoft's command-line shell and scripting language designed for system administration, automation, configuration management, and task orchestration.

Unlike traditional shells that primarily pass text between commands, PowerShell passes objects. This allows commands to work with structured data rather than parsing text output.

PowerShell Editions

• Windows PowerShell 5.1 – Built into Windows.
• PowerShell 7+ – Cross-platform and actively developed.

Launching PowerShell

Windows

• Start Menu → PowerShell
• Windows Terminal
• Win + X menu

Check Version

$PSVersionTable

PowerShell Command Structure

PowerShell commands are called cmdlets.

Verb-Noun

Examples:

Get-Process
Get-Service
Set-Location
Start-Service
Stop-Process

Getting Help

Get-Help Get-Process
Get-Help Get-Service -Examples
Get-Help Get-ChildItem -Full

Discover Commands

Get-Command
Get-Command *process*
Get-Command -Verb Get

Variables

$name = "Alice"
$age = 30

Write-Output $name
Write-Output $age

Useful Variables

$HOME
$PWD
$PSVersionTable

Working with Objects

PowerShell returns objects with properties and methods.

Get-Process

Inspect available properties:

Get-Process | Get-Member

Select specific properties:

Get-Process |
    Select-Object Name, CPU, Id

The Pipeline

The pipeline (|) passes objects from one command to another.

Get-Service |
    Where-Object Status -eq "Running"

Get-Process |
    Sort-Object CPU -Descending |
    Select-Object -First 10

Files and Directories

Get-ChildItem
Get-ChildItem C:\Logs

New-Item file.txt
New-Item FolderName -ItemType Directory

Copy-Item file.txt backup.txt
Move-Item old.txt archive.txt
Remove-Item temp.txt

Aliases

ls
dir
cd
pwd

Filtering Data

Get-Process |
    Where-Object CPU -gt 100

Get-Service |
    Where-Object Name -like "*sql*"

Loops

ForEach

$numbers = 1..5

foreach ($n in $numbers) {
    Write-Output $n
}

For Loop

for ($i = 0; $i -lt 5; $i++) {
    Write-Output $i
}

Conditional Logic

$value = 10

if ($value -gt 5) {
    "Greater than 5"
}
else {
    "5 or less"
}

Comparison Operators

Functions

function Get-Greeting {
    param(
        [string]$Name
    )

    "Hello, $Name"
}

Get-Greeting -Name "Alice"

Working with CSV Files

Import-Csv users.csv

Get-Process |
    Export-Csv processes.csv -NoTypeInformation

Error Handling

try {
    Get-Content missing.txt
}
catch {
    Write-Host "File not found"
}
finally {
    Write-Host "Finished"
}

Remote Administration

Enter-PSSession Server01

Invoke-Command -ComputerName Server01 `
    -ScriptBlock {
        Get-Service
    }

PowerShell Remoting enables remote management across systems.

Useful Everyday Commands

Get-Process
Get-Service
Get-EventLog
Get-Content
Test-Path
Restart-Service
Stop-Process
Get-NetIPAddress
Get-ComputerInfo

Script Example

# Check free disk space

$drives = Get-PSDrive -PSProvider FileSystem

foreach ($drive in $drives) {

    $freeGB = [math]::Round(
        $drive.Free / 1GB,
        2
    )

    Write-Output "$($drive.Name): $freeGB GB Free"
}

Best Practices

• Use descriptive variable names.
• Prefer cmdlets over aliases in scripts.
• Use functions to organize code.
• Add comments where necessary.
• Implement error handling.
• Test scripts in non-production environments first.
• Use PowerShell 7 when possible.

Learning Roadmap

1. Learn cmdlets and help commands.
2. Understand objects and the pipeline.
3. Work with files and directories.
4. Master filtering and sorting.
5. Learn variables, loops, and conditions.
6. Write reusable functions.
7. Create scripts and automation workflows.
8. Explore remoting and administration modules.