Comments and Style

Prerequisites: Script parameters

Comments

# A single-line comment
$taxRate = 0.2  # after code

<#
  A block comment
  spanning several lines
#>

Comment-based help

A special block comment at the top of a script or function becomes help text that Get-Help displays — just like the built-in cmdlets:

function Get-Square {
  <#
  .SYNOPSIS
    Returns the square of a number.
  .PARAMETER Number
    The number to square.
  .EXAMPLE
    Get-Square -Number 7
  #>
  param([double]$Number)
  $Number * $Number
}

Get-Square -Number 7
(Get-Help Get-Square).Synopsis

49
Returns the square of a number.

Style guidelines

The community PowerShell Practice and Style guide recommends:

Full command and parameter names in scripts — no aliases (ls, %, ?) and no positional shortcuts. Get-ChildItem -Path $folder beats gci $folder.
Verb-Noun names with approved verbs for your own functions, and singular nouns (Get-User, not Get-Users).
PascalCase for function and parameter names.
Four-space indentation, and opening braces on the same line.
Output objects, not formatted text, from functions.

PSScriptAnalyzer

PSScriptAnalyzer is the standard linter. It flags aliases, unused variables, missing -WhatIf support, and dozens of other issues:

# illustrative
Install-Module PSScriptAnalyzer -Scope CurrentUser
Invoke-ScriptAnalyzer -Path .\script.ps1

The VS Code PowerShell extension runs it as you type.

What's next

You now know enough PowerShell to automate real tasks. Try the Beginner Projects, then continue to Level 2 — Intermediate, which starts with functions.