PowerShell Basics Guide

Core Philosophy

PowerShell works with objects, not text. Commands pass structured data between each other, making scripting more reliable and powerful.

Command Structure

Verb-Noun Format

All cmdlets follow a consistent Verb-Noun pattern:

• Get-Process - retrieve processes
• Set-Location - change directory
• Stop-Service - stop a service
• New-Item - create a file or folder

Common Verbs

• Get - retrieve data
• Set - change configuration
• New - create something
• Remove - delete something
• Start/Stop - control services/processes
• Import/Export - work with data

Getting Help

PowerShell has excellent built-in documentation:

# Get help for any command
Get-Help Get-Process

# Get detailed help with examples
Get-Help Get-Process -Full
Get-Help Get-Process -Examples

# Update help files (run once)
Update-Help

# Find commands
Get-Command *process*
Get-Command -Verb Get
Get-Command -Noun Service

The Pipeline

The pipeline (|) passes entire objects between commands:

# Get processes, filter by CPU usage, select specific properties
Get-Process | Where-Object {$_.CPU -gt 10} | Select-Object Name, CPU, Memory

# Get services that are running
Get-Service | Where-Object {$_.Status -eq "Running"}

# Get files larger than 1MB
Get-ChildItem | Where-Object {$_.Length -gt 1MB}

Variables

Variables start with $:

$name = "John"
$number = 42
$processes = Get-Process

# Access object properties
$processes[0].Name

Working with Objects

Every object has properties and methods:

# Get an object
$proc = Get-Process -Name "chrome" | Select-Object -First 1

# View all properties
$proc | Get-Member

# Access properties
$proc.Name
$proc.CPU
$proc.WorkingSet

# Call methods
$proc.Kill()

Common Commands

File System

# List files (like ls or dir)
Get-ChildItem
Get-ChildItem -Recurse  # recursive
Get-ChildItem *.txt     # filter

# Change directory
Set-Location C:\Users
cd C:\Users  # alias works too

# Create file/folder
New-Item -Path "test.txt" -ItemType File
New-Item -Path "newfolder" -ItemType Directory

# Copy, Move, Remove
Copy-Item source.txt destination.txt
Move-Item old.txt new.txt
Remove-Item file.txt

Processes

# List processes
Get-Process

# Get specific process
Get-Process -Name chrome

# Stop process
Stop-Process -Name notepad
Stop-Process -Id 1234

Services

# List services
Get-Service

# Control services
Start-Service -Name "wuauserv"
Stop-Service -Name "wuauserv"
Restart-Service -Name "wuauserv"

Filtering and Selecting

Where-Object

Filters objects in the pipeline:

# Filter by condition
Get-Process | Where-Object {$_.CPU -gt 100}
Get-Service | Where-Object {$_.Status -eq "Stopped"}
Get-ChildItem | Where-Object {$_.Length -lt 1KB}

# Shorter syntax (PowerShell 3.0+)
Get-Process | Where CPU -gt 100

Select-Object

Chooses which properties to display:

# Select specific properties
Get-Process | Select-Object Name, CPU, Memory

# Select first/last items
Get-Process | Select-Object -First 5
Get-Process | Select-Object -Last 3

Comparison Operators

-eq   # equal
-ne   # not equal
-gt   # greater than
-lt   # less than
-ge   # greater than or equal
-le   # less than or equal
-like # wildcard match
-match # regex match

Aliases

PowerShell includes familiar aliases:

ls    # Get-ChildItem
dir   # Get-ChildItem
cd    # Set-Location
pwd   # Get-Location
cat   # Get-Content
cp    # Copy-Item
mv    # Move-Item
rm    # Remove-Item
man   # Get-Help

# Find aliases
Get-Alias
Get-Alias -Name ls

Output and Export

# Display as table
Get-Process | Format-Table

# Display as list
Get-Process | Format-List

# Export to CSV
Get-Process | Export-Csv processes.csv

# Export to JSON
Get-Process | ConvertTo-Json | Out-File processes.json

# Save to text file
Get-Process | Out-File processes.txt

Basic Scripting

If Statements

$value = 10
if ($value -gt 5) {
    Write-Host "Greater than 5"
} elseif ($value -eq 5) {
    Write-Host "Equal to 5"
} else {
    Write-Host "Less than 5"
}

Loops

# ForEach
$items = 1..5
foreach ($item in $items) {
    Write-Host $item
}

# ForEach-Object (in pipeline)
Get-Process | ForEach-Object {
    Write-Host $_.Name
}

# While
$i = 0
while ($i -lt 5) {
    Write-Host $i
    $i++
}

Practical Examples

Find large files

Get-ChildItem -Recurse | 
    Where-Object {$_.Length -gt 100MB} | 
    Select-Object Name, Length, FullName | 
    Sort-Object Length -Descending

Monitor CPU usage

Get-Process | 
    Sort-Object CPU -Descending | 
    Select-Object -First 10 Name, CPU, WorkingSet

Find stopped services

Get-Service | 
    Where-Object {$_.Status -eq "Stopped"} | 
    Select-Object Name, DisplayName

Check disk space

Get-PSDrive -PSProvider FileSystem | 
    Select-Object Name, Used, Free, 
        @{Name="UsedGB";Expression={[math]::Round($_.Used/1GB,2)}},
        @{Name="FreeGB";Expression={[math]::Round($_.Free/1GB,2)}}

Tips

1. Tab completion - Press Tab to autocomplete commands and parameters
2. Use Get-Member - Explore what properties and methods objects have
3. ISE or VS Code - Use PowerShell ISE or VS Code for script editing
4. Execution Policy - You may need to run Set-ExecutionPolicy RemoteSigned to run scripts
5. Case insensitive - PowerShell commands are not case-sensitive
6. Comments - Use # for single-line comments, <# #> for multi-line

Next Steps

• Learn about functions and modules
• Explore PowerShell remoting for managing remote computers
• Study error handling with try/catch
• Look into PowerShell profiles for customization
• Practice with real automation tasks