PowerShell. Scripting in Windows Environments Gergő Ládi

Transcription

1 PowerShell Scripting in Windows Environments Gergő Ládi

2 About Me MSc BUTE (BME) Member of KSZK since 2011 Relevant certifications: Gergő Ládi (me@gergoladi.me) 2

3 Outline What is PowerShell? Versions Features Scripting in PowerShell PowerShell 101: cmdlets, aliases, comments, variables, (using) operators, control structures, working with files Advanced scripting: functions of your own, custom aliases, using.net classes, loading dynamic code PSProviders & PSDrives, remoting, package management Gergő Ládi 3

4 CLIs in 2016 :O?! Gergő Ládi

5 CLIs in 2016 :O?! One might be tempted to think that Command Line Interfaces are a thing of the past Both GUIs and CLIs have their own strengths and weaknesses CLIs are more efficient, Less RAM, CPU, disk usage Operations usually take less time to perform Possibility of automation but have a steeper learning curve Unusual, confusing at first Tens (hundreds) of commands with different syntaxes Feedback: less, later Gergő Ládi (me@gergoladi.me) 5

6 What is PowerShell? Gergő Ládi

7 A bit of history COMMAND.COM MS-DOS cmd.exe Windows NT cscript.exe / wscript.exe Windows 98 Monad (2002) -> Windows PowerShell 1.0 (2006) XP SP2, Server 2003, Vista, (WS 2008) 2.0 (2009) Windows 7, Windows Server 2008 R2 3.0 (2011) Windows 8, Windows Server (2013) Windows 8.1, Windows Server 2012 R2 5.0 (2015) Windows 10, Windows Server Gergő Ládi (me@gergoladi.me) 7

8 Notable features Object oriented (1.0) Modular (2.0) PowerShell Remoting (2.0, 3.0) Integrated Scripting Environment (2.0, 3.0) Supports debugging (breakpoints) (2.0) Asynchronous operations (2.0) Transactions (2.0) Desired State Configuration support (4.0, 5.0) Package management support (5.0) Syntax highlighting inside the command line (5.0) Gergő Ládi 8

9 Where is PowerShell used? Windows client operating systems App-V Windows server operating systems Active Directory Microsoft Exchange Skype for Business (formerly Lync) Computer viruses CryptoWall, POSHCODER Gergő Ládi 9

10 PowerShell Gergő Ládi

11 PS Cmdlets Cmdlet: a command that performs operations Not a separate executable May take input from the pipeline and may have an input parameter list Has the form Verb-Noun Get-Help Get-Help Get-Command Get-Help Get-ChildItem Examples Remove-Item C:\Windows\notepad.exe -WhatIf Get-ChildItem -File -Path "C:\Windows" Select-Object Name, Length Sort-Object -Descending Length Gergő Ládi (me@gergoladi.me) 11

12 PS Aliases Alias: a shortcut that invokes a different command (usually one of a longer name) gci, ls, dir -> Get-ChildItem del, rm -> Remove-Item cat, gc -> Get-Content gh, man -> Get-Help To list all available aliases Get-Alias Gergő Ládi (me@gergoladi.me) 12

13 PS Comments Comment: line(s) that are not meant to be interpreted by the parser, but convey information to the (other) programmers # This is a comment. <# This is a multi-line comment #> Get-Help Get-ChildItem # This is an in-line comment Gergő Ládi (me@gergoladi.me) 13

14 PS Variables Variable: a language construct that can be used to store values Must begin with the $ sign, e.g. $MyVariable Working with variables $Name = "Jonathan" # String $Age = 42 # Integer $Hobbies "Sleeping", "F...") # Array $John Name = $Name; Age = $Age; Hobbies = $Hobbies } # Hash $UserDirContents = Get-ChildItem -Path "C:\Users\$Name" Gergő Ládi (me@gergoladi.me) 14

15 PS Variables Working with variables (cont'd) Write-Host "$Name is $Age years old." # Will be substituted Write-Host '$Name is $Age years old.' # Won't be substituted Write-Host "Next year, he'll be $($Age + 1)" # In-line eval. Write-Host "$($John.Name) is a nice guy." # Accessing a member write-host "$NAME FOR PRESIDENT!" # Cmdlet and variable names are case-insensitive Gergő Ládi (me@gergoladi.me) 15

16 PS 101 Operators -lt, -le, -gt, -ge : <, <=, >, >= -eq, -ne : ==,!= -band, -bor, -bxor, -bnot : bitwise operators -contains, -notcontains -like, -notlike, -match, -notmatch Gergő Ládi (me@gergoladi.me) 16

17 PS 101 Using operators Using comparison operators $Age -lt 18 $Name -eq "jonathan" $Name -ceq "jonathan" $Hobbies -contains "Eating" $Name -like "Jo?ath*" " Epoch" -match "\d{4}\.[0-9]{1,2}\.\d{1,2}\. [a-za-z]*" Gergő Ládi 17

18 PS Control structures Control structure: a structure that analyses state information and changes the execution path based on this If, If-Else, If-ElseIf-Else, For, ForEach, While, Examples If ($John.Age -lt 18) { Write-Host "John is under 18!" } ElseIf ($John.Age -eq 18) { Write-Host "John is exactly 18!" } Else { Write-Host "John is over 18! } Gergő Ládi (me@gergoladi.me) 18

19 PS Control structures For ($i = 0; $i -lt 60; ++$i) { Write-Host $i Start-Sleep Milliseconds 100 } ForEach ($Hobby in $Hobbies) { Write-Host "John likes $Hobby" } Gergő Ládi (me@gergoladi.me) 19

20 PS Control structures Write-Host "Starting countdown!" $i = 10 While ($i gt 0) { Write-Host ($i--) Start-Sleep -Milliseconds 100 } Write-Host "Done." Gergő Ládi (me@gergoladi.me) 20

21 PS 101 Working with files $Hobbies Out-File "JohnsHobbies.txt" $Contents = Get-Content JohnsHobbies.txt # Quotes can be omitted $UserDirContents Export-Csv JohnsFiles.csv $ImportedData = Import-Csv JohnsFiles.csv Gergő Ládi (me@gergoladi.me) 21

22 PowerShell Gergő Ládi

23 PS 201 Functions of your own Function: a block of code that can be called multiple times Function Touch-File($File) { If (Test-Path -Path $File) { (Get-ChildItem -Path $File).LastWriteTime = [System.DateTime]::Now } Else { New-Item -Path $File Out-Null } } Gergő Ládi (me@gergoladi.me) 23

24 PS 201 Aliases, $PROFILE New-Alias -Name touch -Value Touch-File touch MyFile.txt # is equivalent to Touch-File File MyFile.txt $PROFILE: a script that is executed each time a shell is opened Add custom function declarations and aliases here to make them permanent Gergő Ládi (me@gergoladi.me) 24

25 PS 201 Using.NET classes It is possible to use any BCL classes from the respective.net Framework version You can also load classes from an external assembly or compile code on-the-fly $Date = [System.DateTime]::Now Gergő Ládi (me@gergoladi.me) 25

26 PS 201 Using.NET classes $TcpClient = New-Object System.Net.Sockets.TcpClient $TcpClient.Connect("max.sch.bme.hu", 25) $TcpClient.ReceiveTimeout = 5000 $Buffer = New-Object Byte[] 1024 $Recvd = $TcpClient.Client.Receive($Buffer) Write-Host ([System.Text.Encoding]::ASCII).GetString($Buffer, 0, $Recvd) Gergő Ládi (me@gergoladi.me) 26

27 PS 201 Using.NET classes $DataToSend = "EHLO" + [Environment]::NewLine $Buffer = [System.Text.Encoding]::ASCII.GetBytes($DataToSend) $TcpClient.Client.Send($Buffer) Out-Null $Buffer = New-Object Byte[] 1024 $Recvd = $TcpClient.Client.Receive($Buffer) Write-Host ([System.Text.Encoding]::ASCII).GetString($Buffer, 0, $Recvd) $TcpClient.Close() Gergő Ládi (me@gergoladi.me) 27

28 PS 201 Loading dynamic code $MyDynamicCode namespace MyNamespace { public static class MyClass { public static int MyFunction(int i){ return 42 2*i; } } } "@ Add-Type TypeDefinition $MyDynamicCode Language Csharp [MyNamespace.MyClass]::MyFunction(10) # Returns Gergő Ládi (me@gergoladi.me) 28

29 PS 201 PSProviders & PSDrives Get-PSProvider Get-PSDrive cd Variable: ls cd HKCU: New-Item -Name "MyKey" -ItemType DWORD -Value Gergő Ládi 29

30 PS 201 PowerShell remoting Enter-PSSession -ComputerName remoteapp whoami hostname Gergő Ládi 30

31 PS 201 Package management Install-Package -Provider bootstrap chocolatey Get-PackageProvider -Name chocolatey Install-Package vlc Gergő Ládi 31

32 Recommended homework Write a PowerShell script that calculates the size of each user's home folder then writes the results to a file, sorted by the total size occupied. Home folders having a size of less than 10 MBs should not appear on the list. Write a PowerShell function that takes a web site URL as a parameter and returns a list of all external JavaScript files on that site Gergő Ládi (me@gergoladi.me) 32

33 Sources Mastering PowerShell (Dr. Tobias Weltner) Windows PowerShell 3.0 Step by Step (Ed Wilson) PowerShell Magazine ( Microsoft Developer Network ( Wikipedia ( Gergő Ládi 33

34 Thank you for your attention! Gergő Ládi

35 Q & A Gergő Ládi (me@gergoladi.me)