Powershell basics

Concepts

• pipes/returns objects instead of text-streams
• cmdlet commands take the formate of <verb>-<noun> ex: Get-Command.
• case-insensitive (if do not like camelcasing, ignore it)
• windows is incapable of something like sudo or su. The cmd/powershell process either has admin privileges or does not. You can spawn a new powershell with admin rights using: Start-Process powershell -Verb runas

Finding Help

There are two variants of the powershell.

• powershell (normal shell)
• powershell ISE (shell/interactive environment)

get-help  <cmdlet-name>                         # display installed help
get-help  <cmdlet-name>  -online                # display help from online
get-help  Write-*                               # help for all cmdlets matching glob-match
Get-Command -?                                  # '-?' == 'Get-Help <cmdlet>'


Get-Command  <cmdlet-match>*                    # search for a specific command
Get-Command  -CommandType <Alias|Function|...>  # restrict search for commands

invocation

This is really important . You cannot directly call a powershell script that contains a space, even if it is in quotes. The method of doing this is different depending on if you are running from a cmd.exe prompt, or a powershell.exe prompt.

# powershell
powershell &'C:\New Folder\myscript.ps1'

REM batch 
powershell -File 'C:\New Folder\myscript.ps1'

comments

test # This is an inline comment

<# 
multiline
comment
#>

variable manipulation

$cwd = get-location                # save output of cmdlet to variable
$cwd                               # print variable
$cwd | get-member                  # list object attributes
$cwd | select-member -property *   # list attributes/values
$cwd.GetType()                     # same as $cwd | get-member

CmdLets

powershell objects are referred to as cmdlets. These builtin cmdlets are designed to interface with the operating system. Some examples:

man pages

Get-Help   <cmdlet-name or command>

filesystem

Get-Disk
Get-Location
Get-ChildItem            ## like unix find

execution policy (run permissions)

Set-ExecutionPolicy  unrestricted   # change what ps scripts are allowed to run
Get-ExecutionPolicy

datetime

Get-Date
Get-TimeZone

symbolic links

NOTE:

Non-Admin powershells do not have sufficient permissions to create symlinks. To enable this set of permissions, you'll need to update your group policy, then logout/login for the change to take effect.

Start Menu > gpedit.msc:
    - Computer configuration > Security Settings > Local Policies > User Rights Assignment:
        - Create Symbolic Links > (double click):
            - Add User or Group: <your username>

New-Item -Path C:/dest -ItemType SymbolicLink -Value C:/src

Process Management

Get-Process    # list all running processes
Get-Service    # list all system services
Get-EventLog   # 

Stop-Process   # kill a process

Registry

Get-ItemProperty -Path 'Registry::HKCU\Environment'
Set-ItemProperty -PATH 'Registry::HKCU\Environment' -Value 'new;path;value'

# checking for/adding to PATH
$PATH = Get-ItemProperty -Path 'Registry::HKCU\Environment' -Name PATH
if (!( $PATH.Path.Split(';').Contains( $rez_PATH ) )){
    Set-ItemProperty -Path 'Registry::HKCU\Environment' -Name PATH -Value ($PATH.Path +";"+ $rez_PATH)
}= Configuration =
<blockquote>


</blockquote><!-- Configuration -->

Downloading

$client = New-Object System.Net.WebClient
$client.DownloadFile("https://bootstrap.pypa.io/ez_setup.py", "ez_setup.py")