PowerShell · ArchWorks

PowerShell is a cross-platform task automation and configuration management framework from Microsoft, consisting of a command-line shell, scripting language, and configuration management system.

Table of Contents#

1. Overview
2. Installation
3. Profile and Customization
4. Variables and Data Types
5. Operators and Pipeline
6. Common Cmdlets Reference
7. File and Directory Operations
8. Error Handling
9. Script Execution Policies
10. Modules
11. Remoting
12. WMI and CIM Queries
13. PowerShell 7 vs Windows PowerShell
Troubleshooting
See Also
Sources

1. Overview#

PowerShell is a task automation and configuration management program from Microsoft, consisting of a command-line shell and the associated scripting language. Unlike traditional shells that pass text between commands, PowerShell passes .NET objects, making data manipulation and filtering more powerful and type-safe.

Key concepts:

Cmdlets - native PowerShell commands following a Verb-Noun naming convention
Pipeline - passes objects (not text) between commands using the | operator
Providers - expose data stores (registry, filesystem, certificates) as navigable drives
Modules - packages of cmdlets, functions, and resources that extend functionality

2. Installation#

PowerShell was made open-source and cross-platform with PowerShell Core (now PowerShell 7+).

Windows#

Download the MSI package from the Official PowerShell Docs.
Alternatively, install via winget or Chocolatey:

# Using winget
winget install Microsoft.PowerShell

# Using Chocolatey
choco install powershell-core

Set up a PowerShell profile in Windows Terminal:

{
    "commandline": "pwsh.exe -nologo",
    "name": "PowerShell",
    "source": "Windows.Terminal.PowershellCore"
}

Linux (Ubuntu 24.04)#

# Update the list of packages
sudo apt-get update

# Install pre-requisite packages
sudo apt-get install -y wget apt-transport-https software-properties-common

# Download the Microsoft repository GPG keys
wget -q "https://packages.microsoft.com/config/ubuntu/24.04/packages-microsoft-prod.deb"

# Register the Microsoft repository GPG keys
sudo dpkg -i packages-microsoft-prod.deb

# Update the list of packages after adding packages.microsoft.com
sudo apt-get update

# Install PowerShell
sudo apt-get install -y powershell

# Start PowerShell
pwsh

macOS#

brew install powershell/tap/powershell

3. Profile and Customization#

The PowerShell profile is a script that runs when a session starts.

# Open your profile script in your default editor
code $PROFILE

# View all profile paths
$PROFILE | Format-List -Force

Profile locations:

Scope	Path
Current User, Current Host	`$PROFILE.CurrentUserCurrentHost`
Current User, All Hosts	`$PROFILE.CurrentUserAllHosts`
All Users, Current Host	`$PROFILE.AllUsersCurrentHost`
All Users, All Hosts	`$PROFILE.AllUsersAllHosts`

Example profile:

# Set aliases
Set-Alias -Name ll -Value Get-ChildItem
Set-Alias -Name np -Value notepad.exe

# Custom prompt
function prompt {
    "$($executionContext.SessionState.Path.CurrentLocation)> "
}

# Import frequently used modules
Import-Module PSReadLine
Set-PSReadLineOption -PredictiveViewStyle ListView

Starship Prompt (Optional)#

Customize the look and feel of PowerShell with the Starship prompt:

# Install Starship
winget install Starship.Starship

# Add to your profile
Add-Content -Path $PROFILE -Value 'Invoke-Expression (&starship init powershell)'

4. Variables and Data Types#

Variable Basics#

# Declare variables ($ prefix required)
$name = "Server01"
$count = 42
$isRunning = $true
$servers = @("Server01", "Server02", "Server03")
$config = @{ Name = "App"; Port = 8080; Enabled = $true }

# Variable types
[string]$hostname = "dc01"
[int]$port = 443
[datetime]$today = Get-Date
[array]$list = 1, 2, 3

# Environment variables
$env:PATH
$env:COMPUTERNAME
$env:USERNAME

Special Variables#

Variable	Description
`$_` or `$PSItem`	Current pipeline object
`$null`	Null value
`$true` / `$false`	Boolean values
`$Error`	Array of recent errors
`$LASTEXITCODE`	Exit code from the last native command
`$PSVersionTable`	PowerShell version information
`$HOME`	User's home directory
`$PWD`	Current working directory
`$args`	Arguments passed to a script or function

String Operations#

# String interpolation (double quotes only)
"Hello, $name. You have $($servers.Count) servers."

# Literal string (no interpolation)
'Hello, $name'

# Here-strings (multiline)
$query = @"
SELECT *
FROM Servers
WHERE Name = '$name'
"@

# Common string methods
$name.ToUpper()
$name.ToLower()
$name.Contains("Server")
$name.Replace("01", "02")
$name.Split("r")

5. Operators and Pipeline#

Comparison Operators#

Operator	Description	Example
`-eq`	Equal	`5 -eq 5`
`-ne`	Not equal	`5 -ne 3`
`-gt`	Greater than	`5 -gt 3`
`-lt`	Less than	`3 -lt 5`
`-ge`	Greater or equal	`5 -ge 5`
`-le`	Less or equal	`3 -le 5`
`-like`	Wildcard match	`"hello" -like "h*"`
`-match`	Regex match	`"hello" -match "^h"`
`-contains`	Collection contains	`@(1,2,3) -contains 2`
`-in`	Value in collection	`2 -in @(1,2,3)`

Logical Operators#

# AND, OR, NOT
($a -gt 5) -and ($b -lt 10)
($a -gt 5) -or ($b -lt 10)
-not ($a -gt 5)

Pipeline#

The pipeline passes objects between cmdlets:

# Filter, sort, and select
Get-Process | Where-Object { $_.CPU -gt 100 } | Sort-Object CPU -Descending | Select-Object -First 5 Name, CPU

# ForEach-Object
Get-Service | ForEach-Object { "$($_.Name): $($_.Status)" }

# Measure results
Get-ChildItem -Recurse | Measure-Object -Property Length -Sum

# Group and aggregate
Get-EventLog -LogName System -Newest 100 | Group-Object -Property Source | Sort-Object Count -Descending

Pipeline Chaining (PowerShell 7+)#

# Run second command only if first succeeds
Get-Process notepad && Stop-Process -Name notepad

# Run second command only if first fails
Get-Process notepad || Write-Host "Notepad is not running"

6. Common Cmdlets Reference#

Getting Help#

# Get help for a cmdlet
Get-Help Get-Process -Full

# Update help files
Update-Help -Force

# Find cmdlets by name pattern
Get-Command -Name *service* -CommandType Cmdlet

# Find cmdlets by verb
Get-Command -Verb Get -Module Microsoft.PowerShell.Management

Process Management#

Get-Process
Get-Process -Name chrome
Stop-Process -Name notepad -Force
Start-Process notepad.exe -ArgumentList "C:\file.txt"
Wait-Process -Name setup

Service Management#

Get-Service
Get-Service -Name wuauserv
Start-Service -Name Spooler
Stop-Service -Name Spooler -Force
Restart-Service -Name Spooler
Set-Service -Name Spooler -StartupType Automatic

Output and Formatting#

# Table format (default for most cmdlets)
Get-Process | Format-Table Name, CPU, WorkingSet -AutoSize

# List format
Get-Service | Format-List *

# Export to CSV
Get-Process | Export-Csv -Path C:\procs.csv -NoTypeInformation

# Export to JSON
Get-Service | ConvertTo-Json | Out-File C:\services.json

# Output to grid view (interactive)
Get-Process | Out-GridView

7. File and Directory Operations#

# List files
Get-ChildItem -Path C:\Users
Get-ChildItem -Path C:\ -Recurse -Filter "*.log" -File

# Create directory
New-Item -Path C:\Temp\Logs -ItemType Directory

# Create file
New-Item -Path C:\Temp\test.txt -ItemType File -Value "Hello"

# Copy
Copy-Item -Path C:\source\* -Destination C:\dest -Recurse

# Move
Move-Item -Path C:\old\file.txt -Destination C:\new\file.txt

# Remove
Remove-Item -Path C:\Temp\old -Recurse -Force

# Read file content
Get-Content -Path C:\log.txt
Get-Content -Path C:\log.txt -Tail 20

# Write to file
Set-Content -Path C:\output.txt -Value "Content"
Add-Content -Path C:\log.txt -Value "New line"

# Test if path exists
Test-Path -Path C:\Temp\file.txt

# Get file properties
Get-ItemProperty -Path C:\file.txt
(Get-Item C:\file.txt).Length
(Get-Item C:\file.txt).LastWriteTime

8. Error Handling#

Try/Catch/Finally#

try {
    $result = Get-Item -Path "C:\nonexistent" -ErrorAction Stop
    Write-Host "Found: $($result.FullName)"
}
catch [System.Management.Automation.ItemNotFoundException] {
    Write-Warning "File not found: $_"
}
catch {
    Write-Error "Unexpected error: $_"
}
finally {
    Write-Host "Cleanup complete"
}

Error Action Preference#

# Per-cmdlet error action
Get-Item -Path "C:\missing" -ErrorAction SilentlyContinue

# Session-wide preference
$ErrorActionPreference = "Stop"

Value	Behavior
`Continue`	Display error and continue (default)
`Stop`	Terminate on error (enables catch)
`SilentlyContinue`	Suppress error and continue
`Inquire`	Prompt user for action

Inspecting Errors#

# View most recent error
$Error[0]
$Error[0].Exception.Message
$Error[0].ScriptStackTrace

# Clear error log
$Error.Clear()

9. Script Execution Policies#

Execution policies control which scripts PowerShell is allowed to run.

# View current policy
Get-ExecutionPolicy
Get-ExecutionPolicy -List

# Set policy
Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser

Policy	Description
`Restricted`	No scripts allowed (default on Windows client)
`AllSigned`	Only scripts signed by a trusted publisher
`RemoteSigned`	Local scripts run freely; downloaded scripts need signature
`Unrestricted`	All scripts run; warns for downloaded scripts
`Bypass`	No restrictions, no warnings

Scopes (in precedence order): MachinePolicy, UserPolicy, Process, CurrentUser, LocalMachine.

10. Modules#

Module Management#

# Find modules in the PowerShell Gallery
Find-Module -Name "*Azure*" | Select-Object Name, Version, Description

# Install a module
Install-Module -Name Az -Scope CurrentUser

# Update a module
Update-Module -Name Az

# Import a module into the current session
Import-Module -Name ActiveDirectory

# List imported modules
Get-Module

# List all installed modules
Get-Module -ListAvailable

# Remove a module from the current session
Remove-Module -Name Az

# Uninstall a module
Uninstall-Module -Name Az

Useful Modules#

Module	Purpose
`PSWindowsUpdate`	Manage Windows Updates
`ActiveDirectory`	AD user/group/computer management
`Az`	Azure resource management
`DnsServer`	Windows DNS Server management
`PSReadLine`	Enhanced command-line editing
`Pester`	Testing framework for PowerShell
`ImportExcel`	Excel import/export without Office

11. Remoting#

PowerShell Remoting uses WS-Management (WinRM) to execute commands on remote computers.

Enable Remoting#

# On the target machine (requires admin)
Enable-PSRemoting -Force

# Test connectivity
Test-WSMan -ComputerName <server-name>

Interactive Session#

# Enter an interactive session
Enter-PSSession -ComputerName <server-name> -Credential (Get-Credential)

# Exit the session
Exit-PSSession

Invoke Commands Remotely#

# Run a command on one or more remote machines
Invoke-Command -ComputerName Server01, Server02 -ScriptBlock {
    Get-Service -Name wuauserv
}

# Run a local script on remote machines
Invoke-Command -ComputerName Server01 -FilePath C:\Scripts\check.ps1

# Run as a background job
$job = Invoke-Command -ComputerName Server01, Server02, Server03 -ScriptBlock {
    Get-EventLog -LogName System -Newest 10
} -AsJob

# Get job results
Receive-Job -Job $job

SSH-Based Remoting (PowerShell 7+)#

# Connect to a Linux host via SSH
Enter-PSSession -HostName <linux-host> -UserName <username>

# Invoke command via SSH
Invoke-Command -HostName <linux-host> -UserName <username> -ScriptBlock {
    uname -a
}

12. WMI and CIM Queries#

CIM (Common Information Model) cmdlets are the modern replacement for WMI cmdlets.

# System information
Get-CimInstance -ClassName Win32_OperatingSystem |
    Select-Object Caption, Version, OSArchitecture, LastBootUpTime

# Disk space
Get-CimInstance -ClassName Win32_LogicalDisk -Filter "DriveType=3" |
    Select-Object DeviceID,
        @{N="SizeGB"; E={[math]::Round($_.Size/1GB,2)}},
        @{N="FreeGB"; E={[math]::Round($_.FreeSpace/1GB,2)}}

# Installed software
Get-CimInstance -ClassName Win32_Product | Select-Object Name, Version

# Network adapters
Get-CimInstance -ClassName Win32_NetworkAdapterConfiguration -Filter "IPEnabled=True" |
    Select-Object Description, IPAddress, DefaultIPGateway, DNSServerSearchOrder

# BIOS information
Get-CimInstance -ClassName Win32_BIOS

# Remote CIM query
Get-CimInstance -ClassName Win32_Service -ComputerName Server01 |
    Where-Object { $_.State -eq "Stopped" -and $_.StartMode -eq "Auto" }

Legacy WMI (Avoid in New Scripts)#

# Old style - use CIM equivalents instead
Get-WmiObject -Class Win32_OperatingSystem

13. PowerShell 7 vs Windows PowerShell#

Feature	Windows PowerShell (5.1)	PowerShell 7+
.NET version	.NET Framework 4.x	.NET 8+
Cross-platform	Windows only	Windows, Linux, macOS
Executable	`powershell.exe`	`pwsh.exe`
Default install	Built into Windows	Separate install
Pipeline chaining	Not available	`&&` and `\|\|` operators
Ternary operator	Not available	`$x ? "yes" : "no"`
Null coalescing	Not available	`$x ?? "default"`
`ForEach-Object -Parallel`	Not available	Available
SSH remoting	Not available	Available
Module compatibility	Full Windows module support	Most modules via compatibility layer

Note: Windows PowerShell 5.1 is still included in Windows and is not being replaced. PowerShell 7 runs side-by-side. Some Windows-specific modules (e.g., ActiveDirectory, GroupPolicy) may only work fully under Windows PowerShell 5.1 or require the Windows Compatibility module.

Troubleshooting#

Issue	Cause	Solution
Script cannot be loaded, execution policy	Execution policy too restrictive	Run `Set-ExecutionPolicy RemoteSigned -Scope CurrentUser`
Module not found after install	Module installed for different scope/version	Check `$env:PSModulePath`; install with `-Scope CurrentUser` or `-Scope AllUsers`
Remoting fails with "access denied"	WinRM not enabled or user lacks permission	Run `Enable-PSRemoting` on target; ensure user is in local Administrators or Remote Management Users group
Cmdlet not recognized	Module not imported or not installed	Run `Get-Module -ListAvailable` to check; install or import the module
Profile not loading	Profile file does not exist	Run `New-Item -Path $PROFILE -Force` to create it
PowerShell 7 missing Windows modules	Module not compatible with .NET Core	Use `Import-Module <name> -UseWindowsPowerShell` for compatibility shim
Slow startup	Heavy profile script	Profile audit: `Measure-Command { pwsh -NoProfile }` vs `Measure-Command { pwsh }`
Object properties appear empty	Using `Format-*` cmdlets mid-pipeline	Move `Format-Table`/`Format-List` to the end of the pipeline only