default Help File

# with paging
help
help default

# no paging
get-help
get-help default

# Category for 'default' help file
get-help -Category HelpFile | where Name -eq default

Get-Help Help File

# with paging
help help
help get-help

# no paging
get-help help
get-help get-help

help about* Help Files

# Read an 'about' topic
help about_<topic>

# List all 'about' topics by wildcard
help about_*

# List all 'about' topics by Category
Get-Help -category HelpFile

Other Help Idioms

# List Help categories
Get-Help * | select Category -unique

# Search help system for text
Get-Help 'Powershell help'

Powershell Environment

# List 'commands' - Alias, Function, Cmdlet
Get-Command
Get-Command * | select CommandType -unique

# List modules
Get-Module -ListAvailable

# PowerShell Version
$PSVersionTable

# PowerShell Edition
#   PowerShell Core emits "Core"
#   PowerShell v5.1 emits "Desktop"
$PSEdition