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Is a shell and programming language designed for task automation and configuration. Aim to replace Batch.

See the powershell-cheat-sheet.pdf - Source


  • Unix is object-based, while Windows is API-based
  • Usually note case-sensitive
  • Commandlets or Cmdlets
    • Verb - Noun
    • Commands are small, so users can write what they want
  • Commands that can be used
    • Specific to PowerShell
    • Standard Windows and Linux via alias
      • Aliases naming is consistent
      • get-alias to list them all
      • get-alias sa* to get all aliases starting with sa
      • get-alias -Definition get-process to get all aliases for command get-process
  • Help system to find how you want to do
    • get-help get-service to bring help on get-service
      • ... -Detailed to have more things, like parameters
      • ... -Full for even more
      • ... -Online to get the web version
      • ... -ShowWindow to get a windowed version of the help
    • get-help about_* for conceptual helps
    • get-help g*service* to list all commands with start with g then have service in the name
    • update-help -Force to update all helps
  • Modules to have more functionalities
    • Get-Module to view currently loaded modules
    • Get-Module - ListAvailable to list all modules



Command Action
# comment Comment
<# comment block #> Comment block
get-service -Name XYZ Call the command get-service with parameter Name and variable XYZ
net view Call the parameter set view of the command net
abc; def Call abc, then def
abc (def) Call def, then abc
abc \| def Call abd, then pipe the output object into def (new line can be added after \| for visibility) (without \)
*string* Wildcard
$_ or $PSItem Current object in the pipeline
{} Script block to be called within another command
$a Call variable a
backtick Escape character, or Go to a next line for clarity in script
Set-PSDebug -Trace 2 Trace everything on the console

Value type

  • Object
    • get-member or gm to find them
    • properties: Thing the object has
      • Can be browsed with . within the object
      • Called ByPropertyX in the documentation
    • method: Thing the object can do
  • String
  • Arrays with []


  • Objects are piped from one command to another using |, not the text representation
  • A carriage return can be done after | for clarity
  • Allow chain of commands like
    • get-service -name bits | stop-service
  • Sender
    • Use gm to find the Type of object sent
  • Receiver
    • Check the documentation to verify if an input can take pipeline get-help abc -Full
      • "Accept pipeline input": true
      • -InputObject xyz[] accept xyz object type - must match the Sender Object Type name
      • Sometime the Receiver that accepts pipe has a different name
    • Sometime the receiver doesn't accept Object
      • Build the sender query and filter using select down to the necessary information
      • Use select -ExpandProperty x to convert to a string
      • Bundle that in parenthesis (get-xyz | select -ExpandProperty y) and pass it as a parameter
      • Dot syntax: (get-xyz).name
      • Script block: get-abc | get-xyz {$_.Name} to do get-abc, then call get-xyz for each value Name of get-abc
  • If the Sender and receiver have a match noun, t

Loops & Conditions

  • foreach {}

Useful commands

  • Some parameter commands are common to any cmdlet - check help about_CommonParameters
    • Output
      • abc -OutVariable a to output to variable a
    • Risk Mitigation
      • abc -whatif: Dry-call the function abc and describe what could happen, without doing it
      • abc -confirm: Call a confirm box before executing abc


  • $MyVar = "hello" to set MyVar to hello
    • $MyVar = Get-service xyz will put the object in it
    • $ is necessary to differentiate variables to programs
    • ${path\to\file} = "content" will assign "content" to a variable stored in path\to\file
  • $MyVar to read it
    • $MyVar.status to get the property status of variable MyVar
      • Sometime the property isn't refreshed in real-time, so maybe you need to call .refresh() or similar
    • $MyVar.stop() to call method stop
  • Remove-Variable to delete a variable
    • Useful in scripts, as a "" variable doesn't have the same effect than a non-existing variable
  • If in a script, parameters variables can also be defined in param () - see PowerShell
  • Advanced help: get-help *variable*
  • Environment variable in Batch are defined as $Env:ENVIRONMENT_VARIABLE_NAME

Interaction with CLI

  • Input
    • read-host
  • Output
    • write-host but consume the object
    • write-output
      • write-warning
      • write-error: throw an error

Interaction with scripts or other commands

  • Get-State A1: Call function Get-State with parameter A1
  • .\script.ps1: Call script.ps1
  • $output = pwd 2>&1
    • 1 is standard output descriptor (stdout) and 2 is error output (stderr) - See about_redirection
    • 2>&1 redirect stream from 2 to 1, > send to file and >> appends

Analysis of output

  • Select-object or select
    • -Property x to show column x only
      • -Property @{n='abc';e={$_.Name}} to create column abc that will contain the Name
        • n for name - or l for label (but it looks like 1)
        • e for expression
      • @{} is a "hash table syntax", documented in manual
    • -ExpandProperty x to convert column x to String
  • Where-object or where
    • { } to define filter
    • Will return $true or $false for each row, and $true objects are kept
    • get-help *comparison* and get-help *operators*
  • sort
  • group
  • split
  • Measure-Command {command} to measure the time command take
  • Tee-Object to copy the output object into something, while passing it to the next in pipe

File manipulation

  • copy-item

Import & Export data

  • compare-object
  • export- have a file output, while ConvertTo- can be piped
  • Text
    • out-file to export content to file
    • get-content
  • CSV
    • export-csv
    • ConvertTo-CSV
    • import-csv
  • XML
    • export-clixml
    • $x = [xml](cat .\file.xml) load file.xml as XML object
      • Can be browsed via x.a[0] to display content of 1st object
      • Or x.a to list everything
  • HTML
    • ConvertTo-html


  • Processes
    • get-process
  • Events
    • get-eventlog


  • Check that you're admin before doing something



Raspberry Pi OS


  • In the console window, right-click on icon -> Properties

Remoting to other PCs

  • Setup
    • Called WinRM - Windows Remote Management
    • Need to be enabled
  • When a script is finished, the session is destroyed
  • Control another PC
    • Enter-PSSession
    • invoke-command or icm
  • Control sessions
    • New-PSSession to open a session, can be assigned to a $var
    • Get-PSSession
  • Use modules from another session
    • Import-PSSession


  • Scripts saved as .ps1 files
  • Modules are saved as .psm1
    • Import via via Import-Module
    • Or place them in directories defined in cat Env:\PSModulePath
      • The name of the subfolder need to be the name of the module file
  • Can be called with .\script.ps1
    • Doesn't work without .\
    • Need the Execution Policy to be set
    • . .\script.ps1 to keep all the script in memory
    • By default, nothing is shown to the user except errors
      • Set-PSDebug -Trace 1 to script each line, and 2 for more - see help
  • The PowerShell ISE can be used as an IDE
    • Auto-completion with CTRL+Space
    • Snippets with CTRL+J
  • param() to set parameters for Variables, set within and the whole script called with -MyVar
    • Mandatory parameters will be called out when calling the function via CLI
      • It's already a string in that case, so no need to put "" for instance!
  • function Verb-Noun{ ... } to set function
  • get-help will work with the script with info in <# #>
Short description

This is the long description

.Parameter MyVar
Description of MyVar

ScriptName -MyVar toto

[CmdletBinding()] # To be able to set variables as mandatory
# Param must be on the 1st line
param (
    $MyVar = 'helloWorld' # Variable that can be passed on as a parameter (-MyVar) with a default variable
    [Parameter(Mandatory=$True)]  # The next variable is mandatory
    [string[]]$MyVar2     # String array variable

function Verb-Noun{ # Start a function
    # Do something
# Call the function


  • New-SelfSignedCertificate
  • Execution Policy direct scripting
    • Get-ExecutionPolicy
    • Set-ExecutionPolicy
      • allsigned: Everything must be signed
        • And ask confirmation if untrusted publisher
      • remotesigned: Remote files must be signed, not local ones
  • get-psdrive will bring you also the Cert drive
    • dir Cert:\CurrentUser -Recurse -CodeSigningCert -OutVariable a to export all code signing certificate
    • $cert = $a[0] to take the 1st certificate from last command
  • Set-AuthenticodeSignature -Certificate $cert -FilePath .\script.ps1 to sign Script.ps1
  • See - Restic Backup for Windows Client for tips on how to enable PowerShell scripts and automate them

External calls

  • Parameters for the PowerShell.exe commands:
    • Path: C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe
    • -Command "Set-Location /path/to/dir" to do a command
    • -Command "& '/path/to/script.ps1' to run a script
    • -File "/path/to/" to run a script
    • -NoExit to keep the window open
    • -WindowStyle Hidden to hide the window - Seems to work only with admin privilege
    • -ExecutionPolicy Bypass to bypass the PowerShell check
  • Scheduling: See Windows Task Scheduler