Skip to content

PowerShell-Basics.md

Latest commit

 

History

History
373 lines (252 loc) · 6.29 KB

PowerShell-Basics.md

File metadata and controls

373 lines (252 loc) · 6.29 KB

⚡ PowerShell Basics

Last updated: February 1, 2026

A practical introduction and daily reference for PowerShell beginners.

What is PowerShell? • Install • Cmdlets • File System • Objects • Variables • Scripts • Control Flow • Functions • Error Handling • Modules • External Systems • Best Practices • Tools • Cheat Sheet

📌 What Is PowerShell?

PowerShell is a cross-platform automation and configuration shell built by Microsoft. It combines:

  • An interactive command-line interface
  • A powerful scripting language
  • Deep integration with .NET, Windows, Azure, and modern APIs

PowerShell is designed for automation, system management, and repeatable workflows across Windows, Linux, and macOS.

1. Getting Started

1.1 Installing PowerShell

Windows / macOS / Linux

  1. Go to the official release page: https://github.com/PowerShell/PowerShell/releases
  2. Download the latest stable installer for your OS.
  3. Install normally.

Running PowerShell

Platform How to Launch
Windows Search PowerShell in Start Menu. Use PowerShell (Core) or Windows PowerShell (legacy).
macOS Open Terminal → pwsh
Linux Open your shell → pwsh

Tip: Prefer PowerShell (Core) for modern scripting.

2. Understanding PowerShell

2.1 Cmdlets

PowerShell commands are called cmdlets (pronounced "command-lets"). They follow a simple naming pattern:

Verb-Noun

Examples

  • Get-Process
  • Set-Location
  • New-Item
  • Remove-Item
  • Get-ChildItem

Discovering Cmdlets

Get-Command
Get-Command -Name *service*

Getting Help

Get-Help Get-Process
Get-Help Get-Process -Examples
Update-Help

3. Navigating the File System

PowerShell treats the file system like a drive.

3.1 Common Commands

Action Command Example
Change directory Set-Location / cd cd C:\Scripts
List items Get-ChildItem / ls ls /var/log
Show current directory Get-Location / pwd pwd

Examples

Set-Location C:\Users
Get-ChildItem -Recurse

4. Working With Objects

Unlike shells that return plain text, PowerShell returns objects.

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

You can pipe objects between cmdlets to filter, sort, or transform them.

Common Object Cmdlets

  • Select-Object
  • Sort-Object
  • Where-Object
  • Format-Table
  • Format-List

Example Pipeline

Get-Process |
    Where-Object { $_.CPU -gt 1 } |
    Sort-Object CPU -Descending |
    Format-Table -AutoSize

5. Variables & Data Types

5.1 Declaring Variables

$name = "Randy"
$count = 5
$items = @(1,2,3)

5.2 Inspecting Types

$name.GetType()

Use $null for empty or missing values.

6. Writing Scripts

PowerShell scripts have the .ps1 extension.

Running a Script

.\myscript.ps1

Execution Policy

If your system blocks script execution:

Set-ExecutionPolicy RemoteSigned -Scope CurrentUser

7. Control Flow

7.1 If/Else

if ($value -gt 10) {
    "High"
} elseif ($value -gt 5) {
    "Medium"
} else {
    "Low"
}

7.2 Loops

Foreach Loop

foreach ($i in 1..5) {
    Write-Output "Number: $i"
}

While Loop

while ($x -lt 10) {
    $x++
}

8. Functions

Functions make your code reusable.

function Get-Greeting {
    param(
        [string]$Name
    )
    "Hello, $Name!"
}

Call it:

Get-Greeting -Name "Randy"

9. Error Handling

9.1 Try/Catch

try {
    Get-Item "C:\does-not-exist.txt"
}
catch {
    Write-Error "File not found!"
}

9.2 Throwing Errors

throw "Something went wrong"

10. Modules

Modules extend PowerShell's capabilities.

10.1 Listing Modules

Get-Module -ListAvailable

10.2 Installing Modules

Install-Module Az
Import-Module Az

11. Working With External Systems

PowerShell integrates easily with REST APIs, cloud platforms, and services.

Example: Calling a REST API

Invoke-RestMethod -Uri "https://api.github.com/repos/PowerShell/PowerShell"

12. Best Practices

  • Use Verb-Noun naming for functions.
  • Validate inputs ([int], [string], etc.).
  • Comment your code for readability.
  • Avoid hardcoding passwords or secrets.
  • Prefer Write-Output over Write-Host.
  • Keep scripts idempotent (safe to run multiple times).
  • Organize related functions into modules.
  • Use consistent indentation and formatting.

13. Helpful Tools

  • VS Code with the PowerShell extension
  • Git + GitHub for source control
  • PSScriptAnalyzer for code quality
  • PowerShell Gallery (https://www.powershellgallery.com/) for modules

14. Quick Reference Cheat Sheet

Common Cmdlets

Purpose Cmdlet
Find commands Get-Command
Get help Get-Help
List files Get-ChildItem
Copy file Copy-Item
Move file Move-Item
Delete file Remove-Item
Check services Get-Service
Stop process Stop-Process

Useful Aliases

ls     # Get-ChildItem
cd     # Set-Location
pwd    # Get-Location

Back to Student Resources

For deeper learning, see the official docs: https://learn.microsoft.com/powershell