Basics

>The Background

• Successor to command.com, cmd.exe, and cscript and has been build-in since Windows 7 and Server 2002 R2
• The standard structure of a command is verb-noun and it supports Object Orientation

>Cmdlets

• Commandlets are simple programs that let us get stuff done and they follow the verb-noun pattern

Get-Command set* #show cmdlets starting with set
Get-Command #show all the cmdlets that powershell knows about
Get-Command -verb "keyword" #show all the verbs with the corresponding keyword
Get-Command -noun "keyword" #show all the corresponding nouns

cmdlet -whatif #show what will happen after this cmdlet is executed

• Some of the common verbs are Set-, Get-, New-, Read-, Find-, Start-

>Cmdlet Aliases

Many cmdlets have aliases making them much easier to use

#We can use the alias command to show all the aliases that are there
alias

CommandType     Name
-----------     ----                                              
Alias           ? -> Where-Object                                 
Alias           % -> ForEach-Object                               
Alias           cd -> Set-Location

[redacted for brevity]

#To get alias for a specific cmdlet
Get-Alias -definition <cmdlet>f

>Getting Help

• We can use either Get-Help cmdlet or its alias help

help [cmdlet/ alias]
help [cmdlet] -detailed
help [cmdlet] -examples
help [cmdlet] -full
help [cmdlet] -online 

>The Pipeline

• When we use | b/w cmdlets, we are not piping streams of actual data, we're piping the objects (which makes it so powerful) viz. we don't have to parse and can just pull out stuff from the passed-on object we want.

#Show a list of methods and properties of each object 
cmdlet | Get-Member
cmdlet | Format-List 
cmdlet | Format-List -property [property]
cmdlet | Format-List -property * 

>Working with objects in the pipeline

<aside> 👉 ForEach-Object % {$_})

</aside>

• ForEach-Object is aliased with %
• If we pipe another command's output to it, it will operate on each object passed down the pipeline and the current object will be referred to as $_

Get-Process -name nc | % {stop-process $_}
Get-Process -name nc | ForEach-Object {stop-process $_}

100, 200, 500 | % {$_ * 50}
100, 200, 500 | ForEach-Object {$_ * 50}

<aside> 👉 Where-Object ? {$_})

</aside>

• Used to filter object passed down to the pipeline based on their properties

Get-Command | Get-Member
Get-Command | Where-Object {$_.status -eq "running"}
Get-Command | ? {$_.status -eq "running"}

>Environment Variables

• For regular variables, prepend a $ and for environment variables prepend $env:

ls env:
ls variable: