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PowerShell Basics

Summary

Essential information for getting started with PowerShell including versions, environments, and execution policies.

What is PowerShell?

PowerShell is a task automation and configuration management framework from Microsoft. It consists of:

  • A command-line shell for running commands
  • A scripting language for automation
  • A framework for managing systems

PowerShell vs CMD vs Bash

# PowerShell - Works with objects
Get-Process | Where-Object {$_.CPU -gt 100} | Select-Object Name, CPU

# CMD - Works with text
dir | find "txt"

# Bash - Works with text
ls | grep "txt"

Key Differences:

  • PowerShell: Object-oriented, structured data, powerful pipeline
  • CMD: Text-based, limited functionality, legacy Windows
  • Bash: Text-based, powerful in Linux/Unix, text parsing required

Why PowerShell?

PowerShell works with objects, not text. This means you get structured data with properties and methods, making automation much easier than parsing text output.

PowerShell Versions

Windows PowerShell (5.1)

  • Built into Windows 10/11 and Windows Server
  • Based on .NET Framework
  • Windows-only
  • This is what you have by default on Windows
# Check version
$PSVersionTable

# Output shows:
PSVersion: 5.1.xxxxx

PowerShell 7+ (Cross-Platform)

  • Open-source, cross-platform (Windows, Linux, macOS)
  • Based on .NET Core/.NET 6+
  • Faster, more features
  • Installed separately (doesn't replace 5.1)
# Check version
$PSVersionTable.PSVersion

# Output shows:
Major  Minor  Patch
7      4      0

Which Version Should I Use?

  • Learning? Either works, but 7+ is recommended for new features
  • Work environment? Use what's installed (usually 5.1)
  • Personal projects? Install PowerShell 7+ for latest features

To install PowerShell 7+: 

# Using Windows Terminal/PowerShell
winget install Microsoft.PowerShell

PowerShell Environments

PowerShell Console (Default)

The basic blue PowerShell window:

  • Built into Windows
  • Limited features
  • Works but not ideal for development

How to open:

  • Start Menu → Search "PowerShell"
  • Win + X → "Windows PowerShell"

Windows PowerShell ISE

Integrated Scripting Environment - comes with Windows:

  • Script editor + console
  • Syntax highlighting
  • IntelliSense (autocomplete)
  • Debugging tools
  • Only supports PowerShell 5.1 (not 7+)

How to open:

  • Start Menu → Search "PowerShell ISE"

ISE is Legacy

ISE is deprecated and won't get new features. It's fine for quick scripts but VS Code is recommended for serious work.

Modern, powerful code editor:

  • Works with PowerShell 5.1 and 7+
  • Excellent PowerShell extension
  • Git integration
  • Best IntelliSense
  • Debugging
  • Integrated terminal

Setup: 1. Install VS Code: https://code.visualstudio.com 2. Install PowerShell extension (by Microsoft) 3. Configure integrated terminal to use PowerShell

Windows Terminal (Best Console)

Modern terminal app from Microsoft:

  • Tabs, panes, beautiful themes
  • Works with PowerShell, CMD, WSL, etc.
  • Unicode support
  • GPU-accelerated

To install: 

winget install Microsoft.WindowsTerminal

Recommended Setup

For beginners: Windows Terminal + PowerShell 7 For scripting: VS Code + PowerShell extension For quick commands: Windows Terminal

Execution Policies

Execution policies control whether PowerShell scripts can run. This is a safety feature, not security.

Policy Levels

# Check current execution policy
Get-ExecutionPolicy

# Common policies:
Restricted       # No scripts allowed (default on some systems)
AllSigned        # Only signed scripts
RemoteSigned     # Local scripts OK, remote must be signed (recommended)
Unrestricted     # All scripts allowed (prompts for remote)
Bypass           # Nothing blocked, no warnings

Setting Execution Policy

# Set for current user (recommended, doesn't need admin)
Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser

# Set for entire machine (needs admin)
Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope LocalMachine

# Temporarily bypass for one session
PowerShell.exe -ExecutionPolicy Bypass -File "C:\Scripts\myscript.ps1"

Common Beginner Issue

If you get "cannot be loaded because running scripts is disabled", you need to set execution policy: 

Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser

Understanding Remote Scripts

When you download a script from the internet, Windows marks it as "from another computer":

# Check if file is blocked
Get-Item C:\Scripts\downloaded.ps1 | Get-Item -Stream Zone.Identifier

# Unblock a downloaded script
Unblock-File -Path C:\Scripts\downloaded.ps1

# Unblock all scripts in a folder
Get-ChildItem -Path C:\Scripts -Recurse | Unblock-File

Running PowerShell Scripts

Method 1: From PowerShell Console

# Navigate to script folder
cd C:\Scripts

# Run script (note the .\ prefix)
.\myscript.ps1

# Or use full path
C:\Scripts\myscript.ps1

# Run with parameters
.\myscript.ps1 -Name "John" -Age 30

Must Use .\ or Full Path

myscript.ps1        # Won't work!
.\myscript.ps1      # Works
PowerShell doesn't run scripts from current directory without .\ for security.

Method 2: Right-Click Context Menu

Right-click a .ps1 file:

  • "Run with PowerShell" - Runs and closes immediately
  • "Edit" - Opens in ISE (if installed)

Right-Click Issues

"Run with PowerShell" closes the window immediately. Add Read-Host "Press Enter to exit" at the end of your script to keep it open.

Method 3: From CMD or Run Dialog

powershell.exe -File "C:\Scripts\myscript.ps1"

REM Or execute command directly
powershell.exe -Command "Get-Process | Where-Object {$_.CPU -gt 100}"

Method 4: Scheduled Tasks

Create a scheduled task:

  • Program: powershell.exe
  • Arguments: -ExecutionPolicy Bypass -File "C:\Scripts\myscript.ps1"

PowerShell Profile

Your profile is a script that runs automatically when PowerShell starts. Use it for customization:

# Check if profile exists
Test-Path $PROFILE

# Create profile if it doesn't exist
if (!(Test-Path $PROFILE)) {
    New-Item -Path $PROFILE -ItemType File -Force
}

# Edit profile
notepad $PROFILE
# Or in VS Code:
code $PROFILE

Common Profile Customizations

# Example profile contents

# Custom prompt
function prompt {
    "PS [$env:USERNAME@$env:COMPUTERNAME] $(Get-Location)> "
}

# Aliases
Set-Alias -Name np -Value notepad
Set-Alias -Name ll -Value Get-ChildItem

# Custom functions
function Get-MyIP {
    (Invoke-WebRequest -Uri "https://api.ipify.org").Content
}

# Set default location
Set-Location C:\Scripts

# Load modules
Import-Module MyCustomModule

# Display welcome message
Write-Host "Welcome back, $env:USERNAME!" -ForegroundColor Green

Profile Locations

# Current user, current host
$PROFILE

# Current user, all hosts
$PROFILE.CurrentUserAllHosts

# All users, current host
$PROFILE.AllUsersCurrentHost

# All users, all hosts
$PROFILE.AllUsersAllHosts

PowerShell Basics - Quick Start

Starting Your First Session

# Check version
$PSVersionTable.PSVersion

# Get current location
Get-Location

# List files
Get-ChildItem

# Change directory
Set-Location C:\Temp

# Clear screen
Clear-Host
# Or just: cls

# Get command history
Get-History

# Exit PowerShell
exit

Tab Completion

PowerShell has excellent tab completion:

# Type partial command and press Tab
Get-Pro[Tab]        # Cycles through Get-Process, Get-ProvisioningPackage, etc.

# Tab complete parameters
Get-Process -[Tab]  # Cycles through -Name, -Id, -ComputerName, etc.

# Tab complete file paths
cd C:\Pro[Tab]      # Expands to C:\Program Files\

# Ctrl+Space shows all options
Get-Process [Ctrl+Space]  # Shows all available parameters

Command History

# Use arrow keys
↑ (Up Arrow)        # Previous command
↓ (Down Arrow)      # Next command

# Search history
Ctrl+R              # Reverse search (type to search)

# Get history
Get-History

# Run command from history
Invoke-History 5    # Runs command #5 from history

# Run last command
!!                  # In PowerShell 7+

Common Beginner Mistakes

Mistake 1: Not Setting Execution Policy

# Error: "cannot be loaded because running scripts is disabled"

# Fix:
Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser

Mistake 2: Forgetting .\ When Running Scripts

# Wrong:
myscript.ps1        # Error!

# Right:
.\myscript.ps1      # Works

Mistake 3: Using Wrong Operators

# Wrong (from other languages):
if ($x == 5) { }    # Error!
if ($x > 5) { }     # Error!

# Right (PowerShell way):
if ($x -eq 5) { }   # Correct
if ($x -gt 5) { }   # Correct

Mistake 4: Not Checking Variable Existence

# Dangerous:
$result = $myVariable.Property  # Error if $myVariable is null

# Safe:
if ($null -ne $myVariable) {
    $result = $myVariable.Property
}

Tips & Tricks

Quick Clear Screen

Clear-Host    # Long way
cls           # Alias (same as CMD)
Ctrl+L        # Keyboard shortcut

Stop Running Command

Ctrl+C        # Stops current command
Ctrl+Break    # Harder stop if Ctrl+C doesn't work

Copy/Paste in Console

# In Windows Terminal:
Ctrl+C        # Copy selected text
Ctrl+V        # Paste

# In old PowerShell console:
Right-click   # Paste
Select text + Enter  # Copy

Get Command Path

# Find where a command is located
Get-Command powershell.exe
(Get-Command code).Source

PowerShell Remembers Your Location

# Each PowerShell window remembers its own current directory
cd C:\Temp
# Close and reopen - you're back at default location

# Use profile to always start in specific location:
Set-Location C:\Scripts  # Add this to $PROFILE

Execution Policy is Per-User by Default

# Setting for CurrentUser doesn't affect other users
Set-ExecutionPolicy RemoteSigned -Scope CurrentUser

# Other users on same machine will have their own policy

Additional Resources