SlideShare a Scribd company logo

Power shell training

•Download as PPTX, PDF•
•
David Brabant
David Brabant

This document provides information about PowerShell training offered by David Brabant in August 2014. It discusses PowerShell versions and features, common PowerShell hosts like the console and PowerShell ISE, PowerShell security including signing scripts and execution policies, and anatomy of PowerShell scripts including variables, functions, and modules. PowerShell allows administrators to script and automate tasks across Windows platforms and other systems like AWS. It is an essential tool for system administrators and DevOps.

1 of 57
www.evs.com PowerShell Training David Brabant 08/2014
2
In Windows’ world, PowerShell allows to script and automate everything but the kitchen sink Windows Server - Active Directory - Internet Information Server - NLBS, fail over clustering, group policies, backups, scheduling tasks … - HyperV Windows Management & Instrumentation (WMI) SQL Server Exchange Server SharePoint Azure But also outside Windows’ world Amazon AWS PowerShell is an essential tool for sysadmins and devOps 3 PowerShell is Everywhere
4 PowerShell Versions PowerShell 1 PowerShell 2 PowerShell 3 PowerShell 4 PowerShell 5 WXP SP2 WS 2003 Optional on WS 2008 W7 WS 2008 R2 Installable on: WXP SP3 WS 2003 SP3 W8 WS 2012 Installable on: W7 SP1 WS 2008 SP1 WS 2008 R2 SP1 W8.1 WS 2012 R2 Installable on: W7 SP1 WS 2008 R2 SP1 WS 2012 Installable on same platforms as PowerShell 4
5 PowerShell Features PowerShell 1 PowerShell 2 PowerShell 3 PowerShell 4 PowerShell 5 Initial version (2006) New cmdlets Remoting Background jobs Modules Transactions Debugging Eventing Exception handling PowerShell ISE New cmdlets New modules Workflows (WWF) Schedulled jobs WebAccess Remote sessions tolerant to network failures Updatable help Code completion in ISE New cmdlets New modules Desired state configuration (DSC) Enhanced debugging Network diagnostics New cmdlets New modules Support for Chocolatey (aka apt-get for Windows)
6 PowerShell Hosts The good ole’ console (real men use the command line)
7 PowerShell Hosts The PowerShell ISE
PowerGUI 8 PowerShell Hosts • Free (brought to you by Dell) • Better debugging than PS ISE • Plugin for Visual Studio
9 PowerShell Hosts Based on their own PowerShell host applications i.e.: they don’t use powershell.exe SQLPS.exe for SQLServer Devenv.exe for Visual Studio
Two versions of PowerShell on a 64bit machine - 32Bit: C:WindowsSysWOW64WindowsPowerShellv1.0powershell.exe - 64Bit: C:WindowsSystem32WindowsPowerShellv1.0powershell.exe Might be important to know when you use some PowerShell modules E.g.: you have a 32bit SQLServer installed on your 64bit machine and you want to import the SQLPS module. Wont’ work in PowerShell 64bit, will work like a charm on PowerShell 32bit… 10 Before going further: PowerShell Traps & Pitfalls Yeah, right!
How do I know which version of PowerShell I’m running? $PSVersionTable $Host How do I know if I’m running the 64bit or the 32bit version? [IntPtr]::size -eq 8 #64bit [IntPtr]::size -eq 4 #32bit 11 PowerShell Traps & Pitfalls
Profiles allow to gather things you use frequently (aliases, modules, functions…) They are loaded when PowerShell starts 4 different profiles - %windir%system32WindowsPowerShellv1.0profile.ps1 This profile applies to all users and shells - %windir%system32WindowsPowerShellv1.0Microsoft.PowerShell_profile.ps1 This profile applies to all users, but only to the Microsoft.PowerShell shell - %UserProfile%My DocumentsWindowsPowerShellprofile.ps1 This profile applies only to the current user, but affects all shells - %UserProfile%My DocumentsWindowsPowerShellMicrosoft.PowerShell_profile.ps1 This profile applies only to the current user and the Microsoft.PowerShell shell 12 PowerShell Profiles
One thing you should put in your profile Beware of the formatting gremlins 13 PowerShell Traps & Pitfalls
Scripts are good things, scripts are bad things - Consistent and repeatable administration of IT resources but … - PowerShell scripts can do anything in your Windows environment - … and that’s a wide open door for introducing malware in your walls - Users can (and will) execute scripts without really understanding what they are doing PowerShell intends to create a «secure by default» environment for running scripts - The shell makes it difficult for users to run scripts without realizing they are doing so - The default configuration is not convenient, but you can reconfigure execution policies - Multiple security options help you to find a balance between convenience and security 14 PowerShell Security
Policy Name Description Restricted (default) Scripts won’t run. Period. RemoteSigned Scripts created locally will run. Those downloaded from Internet won’t unless they are signed by a trusted publisher (use the 'Zone.Identifier' alternate data stream) AllSigned Scripts will only run if they are digitally signed by a trusted publisher Unrestricted Scripts will run regardless of their provenance, signed or not. You are on your own, dude 15 PowerShell Execution Policies • Get-ExecutionPolicy • Set-ExecutionPolicy • Get-Help about_Execution_Policies
Two steps process 1. Create a certificate (if you don’t already have one) 2. Sign your script Something like this appears at the end of your script 16 Signing Scripts PowerShell Provider
17 Anatomy of a PowerShell Script cmdlets built-in functions logical constructs
PowerShell commands are implented as cmdlets or as built-in functions A cmdlet is a lightweight command implented as a .Net class They are not stand-alone executables (i.e.: they are only available in a PowerShell context) You can very easily create your owns, with a little bit of C# Built-in functions are implemented in PowerShell Tip: How do I get a list of known, globally scoped, functions (builtin/user)? cd function: dir Tip: How do I see the content of a built-in function? ${function:clear-host} 18 Anatomy of a PowerShell Script PowerShell Provider
How do I get a list of all known PowerShell commands? Get-Command | more How do I get help for a given command? Get-Help <Command> How do I get help for a specific topic? Get-Help about Example: Get-Help about_Workflows How can I be sure I’m using the latest help available? Update-Help # Of course, you need Internet access… 19 PowerShell Help Will provide a (looong) list of topics for which you can get help: things like debugging, jobs, workflows, parsing, regexs …
20 PowerShell Verb-Noun Conventions All PowerShell cmdlets follow some naming conventions How do I get a list of PowerShell approved verbs and their conventional meaning? Get-Verb These conventions are not strictly mandatory, but it is strongly advised to follow them Commands and variables are case-insensitive High consistency in parameters naming and conventions across all cmdlets Get-Help about_CommonParameters An example: all potentially harmful commands have a –WhatIf parameter del *.txt –WhatIf will list all files that would be deleted executing the command POLA (Principle Of Least Astonishment) The common parameters are a set of cmdlet parameters that you can use with any cmdlet. They are implemented by PowerShell, not by the cmdlet developer, and they are automatically available to any cmdlet.
Variable names start with $ ${this variable name is "unusual," but permitted} = "Hello World" Dynamicaly typed $x = "5" What will be the result of $x + 3 ? You can be explicit [int] $x = "5" What will be the result of $x + 3 ? Cast $x = [int] "5" Once a type has been explicitly set, it cannot be changed [int] $x = 3; $x = Get-Date $x = 3; $x = Get-Date  Multiple assignments $a = $b = $c = 1 $Value1, $Value2 = 10,20 21 PowerShell Variables Any .Net type
Scope modifiers global, local, script, private Get-Help about_Scopes To explicitly modify a scope, the syntax is $<scope>:<name> $global:xyzzy = 42 $local:foobar = Get-FooBar function private:Hello { Write-Host ‘Hello’ } Or Set-Variable –scope Global –name plugh –value 10 An item you include in a scope is visible in the scope in which it was created and in any child scope, unless you explicitly make it private. You can place variables, aliases, functions in one or more scopes An item that you created within a scope can be changed only in the scope in which it was created, unless you explicitly specify a different scope 22 PowerShell Scopes No $ prefix!
How do I know variables defined in a given scope? Get-Variable -scope <scope> How do I list global variables and their values? cd variable: dir Special variables $_ – Contains the current pipeline object, used in script blocks, filters, and the where statement $Args – Contains an array of the parameters passed to a function $Error – Contains objects for which an error occurred while being processed in a cmdlet $Home – Specifies the user’s home directory $PsHome – The directory where the Windows PowerShell is installed Environment variables $env:<variable> (ex.: $env:COMPUTERNAME, $env:Path) 23 PowerShell Variables More on that later
Variables are expanded in double-quoted strings Variables are not expanded in single-quoted strings $name = "David" Write-Host "Howdy $name" # Output: Howdy David Write-Host 'Ahoy $name' # Output: Ahoy $name Avoiding expansion in double-quoted strings through escaping Write-Host "Howdy `$name" # Output: Howdy $name Backtick ( ` ) as escaping character Escaping a double quote in a double-quoted string Write-Host "Howdy `"$name`"" # Output: Howdy "David" Some escaped sequences have special meanings `t = TAB `r = carriage return `r`n = carriage return + line feed 24 PowerShell Variables Expansion and Escaping
Like in Unix, most of cmdlets can be piped dir –recurse | where { $_.LastWriteTime -gt (Get-Date).AddDays(-5) } | sort Length User functions can be pipe-able too 25 PowerShell Pipeline These commands are aliases
Synonyms for cmdlets and functions dir = Get-ChildItem del = Remove-Item where = Where-Object sort = Sort-Object How do I get a list of aliases? Get-Alias How do I get definition for a specific alias? Get-Alias <command> (ex: Get-Alias dir) How do I define my own aliases? Set-Alias (ex: Set-Alias n++ "C:Program Files (x86)Notepad++notepad++.exe") How do I remove an alias Remove-Item alias:<command> (ex: Remove-Item alias:dir) 26 PowerShell Aliases
• for($i = 0; $i -le 10; ++$i) { Write-Host "Hello World" } • foreach($i in 0..9) { Write-Host "Hello World" } • $i = 0; do { Write-Host "Hello World"; ++$i } while ($i -le 10) • $i = 0; while ($i -le 10) { Write-Host "Hello World"; ++$i } • break, continue 27 PowerShell Basic Language Constructs: Loops PowerShell Traps & Pitfalls
$i = 5; if ($i -gt 3 -and $i -lt 8) { Write-Host "Yepeee" } $a = 5 switch ($a) { 1 {"The color is red."} 2 {"The color is blue."} 3 {"The color is green."} 4 {"The color is yellow."} 5 {"The color is orange."} 6 {"The color is purple."} 7 {"The color is pink."} 8 {"The color is brown."} default {"The color could not be determined."} } 28 PowerShell Basic Language Constructs: Conditional Statements PowerShell Traps & Pitfalls
The value of $true is … True The value of $false is … False What is the value of $true -eq $false ? What is the value of $true -eq "False" ? 29 PowerShell Traps & Pitfalls: $true, $false $true $false $true $false Any string of length > 0 Empty string Any number > 0 Any number = 0 Array of length > 1 Array of length 0 Array of length 1 whose element is true Array of length 1 whose element is false A reference to any object $null
30 PowerShell Basic Language Constructs: try/catch/finally back tick to split single command on multiple lines catching specific .Net exceptions One of the common parameters for cmdlets Stop Continue SilentlyContinue Inquire
31 PowerShell Functions Not mandatory to specify a type Alternative (prefered) syntax PowerShell Traps & Pitfalls One of the main sources of errors when you learn Powershell Calling functions with multiple parameters: NO COMMA, NO PARENTHESIS in function calls, unless you are calling .Net native functions (more on that later)
Function parameters can be decorated with attributes telling - Their type - If they are mandatory or not - If they have default value - If they can accept values from pipeline - If they are « switch » parameters - Their position and name - … $Args inside a function contains an array with all parameters at call time 32 PowerShell Function Parameters
33 PowerShell Traps & Pitfalls Comma is the array construction operator A comma on indicates a collection of objects bound to one parameter PowerShell tip: use Set-ScrictMode at the beginning of your scripts Checks the following items: • References to uninitialized variables, both directly and from within strings • References to non-existent properties of an object • Calling a function like a method
$states = @{"Washington" = "Olympia"; "Oregon" = "Salem"; California = "Sacramento"} $states # Let’s display the content of $states Name Value ---- ----- California Sacramento Washington Olympia Oregon Salem # Let’s add a key/value $states.Add("Alaska", "Fairbanks") $states | Get-Member One of the most usefull and underused function in PowerShell 34 PowerShell Hashtables TypeName: System.Collections.Hashtable Name MemberType Definition ---- ---------- ---------- Add Method void Add(System.Object key, System.Object … Clear Method void Clear(), void IDictionary.Clear() Clone Method System.Object Clone(), System.Object ICloneable.Clone() Contains Method bool Contains(System.Object key), bool … ContainsKey Method bool ContainsKey(System.Object key) ContainsValue Method bool ContainsValue(System.Object value) CopyTo Method void CopyTo(array array, int arrayIndex), … Equals Method bool Equals(System.Object obj) GetEnumerator Method System.Collections.IDictionaryEnumerator GetEnumerator(), … GetHashCode Method int GetHashCode() GetObjectData Method void GetObjectData(System.Runtime.Serialization… GetType Method type GetType() OnDeserialization Method void OnDeserialization(System.Object sender), … Remove Method void Remove(System.Object key), void … ToString Method string ToString() Item ParameterizedProperty System.Object Item(System.Object key) {get;set;} Count Property int Count {get;} IsFixedSize Property bool IsFixedSize {get;} IsReadOnly Property bool IsReadOnly {get;} IsSynchronized Property bool IsSynchronized {get;} Keys Property System.Collections.ICollection Keys {get;} SyncRoot Property System.Object SyncRoot {get;} Values Property System.Collections.ICollection Values {get;}
35 Documenting PowerShell Functions A structured multi-lines comment in function’s header, before the param block HowTo here
36 Documenting PowerShell Functions
Assigning PowerShell code to a variable (aka anonymous functions or lambdas) Can be used as parameter to functions $x = { Write-Host "Hello, World!" } $x.GetType() # IsPublic IsSerial Name BaseType # -------- -------- ---- -------- # True False ScriptBlock System.Object $x # What's the content of $x? # Output: Write-Host "Hello, World!" # Let's invoke the script block $x.Invoke() # Output: Hello, World! 37 PowerShell Script Blocks
A PowerShell script having .psm1 as its file extension (.ps1 for standard scripts) Gathering reusable functions, variables, aliases… Loaded in your scripts through Import-Module <path to your .psm1 file> -DisableNameChecking –Force You can put that in your profile.ps1 file Functions, variables, aliases you want to make available outside your .psm1 file must be explictly exported At the end of the module file, you typically find Export-ModuleMember -function * # * = all. But can be comma separated function list Export-ModuleMember -variable * 38 PowerShell Modules Avoid warnings if you haven’t followed PowerShell naming conventions (verb-noun) Forces load of your module (usefull when you modify it while writing and debugging your scripts)
39 PowerShell Structured Objects (PSObjects) PowerShell Traps & Pitfalls Use $($object.Field) for expanding structured objects in strings • PowerShell has no concept of a class, so classical inheritance is not an option However, PowerShell’s Adaptive Type System (ATS) gives us great power in implementing prototypal objects, and mixins • Easily persist PSObjects to files through Export-CliXML / Import-CliXML
40 PowerShell and .CSV Files Shortcut for foreach
PowerShell is really your friend whent it comes to handle XML files Anything you can do in .Net (xpath, xquery, xslt…), you can do it simpler in PowerShell Can’t explain it all on one slide… Just a small example for changing all connection strings in App.config 41 PowerShell and .XML Files Get-Content normaly returns an array of strings. Here that array is casted to an XML document
42 PowerShell and .JSON Files ConvertFrom-Json ConvertTo-Json Extremely useful with: Invoke-RESTMethod Invoke-WebRequest
43 PowerShell and WebServices This is a COM object … and this is its ComID Don’t forget about Get-Member $IE | Get-Member will produce a list of methods And properties for IE
44 PowerShell and Invoking .Net Classes Add-Type –AssemblyName System.EnterpriseServices is the new PowerShell 3 way. Prefer it when you can.
45 PowerShell and In-line C# Code Calling a static method Calling a standard method requires an instance
Connects two copies of PowerShell over the network The «client copy» (where you sit) sends commands to one or more «server copies» (remote machines) Remote machines execute commands locally, and send back resulting objects Relies on PSSession, an object that represents an authenticated connection between two computers $s1 = New-PSSession -ComputerName Server1 –Authentication <Some Authentication> Invoke-Command -Session $s1 -ScriptBlock { <Some PS code> } -AsJob Persists the connection in a variable, persists multiple connections in an array «Persist» does not mean «constantly send traffic»; it reconnects on demand invisibly Easy to setup in Windows domains, a little bit trickier for workgroups 46 PowerShell Remoting
47 PowerShell Remoting • Uses HTTP and HTTPS as the underlying transport, on port 5985 (default) • Communications are handled by Windows Remote Management (WinRM), a service that implements Web Services for Management (aka WS-MAN) • PWA (PowerShell Web Acces in Windows Server 2012) Gives you a PowerShell Console in your web brower • http://powershell.org/wp/ebooks/ Secrets of PowerShell Remoting (and other free e-books)
$job = Start-Job -ScriptBlock { Get-Process } Get-job $job.Name Receive-Job $job.Name 48 PowerShell and Background Jobs Your background job Get-Help about_Jobs Get-Help about_Job_Details Get-Help about_Remote_Jobs
PowerShell 3.0 or later Integration with Windows Workflow Foundation Each activity of the workflow can run in its own runspace, possibly remotely Variables that are created at the top level of the entire workflow are available throughout the workflow Workflows can be designed through the Visual Studio Workflow Designer Get-Help about_Workflow_Common_Parameters Get-Help about_Workflows 49 PowerShell and Workflows
50 PowerShell and Workflows
«Mount» hierarchical structures as if they were a virtual file system Get-Help about_Providers Often used by Microsoft’s PowerShell modules to abstract and ease access to their own software (Active Directory, Exchange, IIS, SQLServer, SharePoint…) You can easily implement your own (XT3 PowerShell Provider, anyone?) 51 PowerShell Providers
Import-Module sqlps -DisableNameChecking Anything you can do from SQL Enterprise manager, you can script it from PowerShell 52 PowerShell and SQLServer Provider SQL Server data store root SQLSERVER: Network root SQLSERVER:SQL Instances on selected machine SQLSERVER:SQLmachine Top-level objects in selected instance SQLSERVER:SQLmachineinstance Databases in selected instance SQLSERVER:SQLmachineinstanceDatabases Top-level objects in selected database SQLSERVER:SQLmachineinstanceDatabasesdatabase Tables in selected database SQLSERVER:SQLmachineinstanceDatabasesdatabaseTables Views in selected database SQLSERVER:SQLmachineinstanceDatabasesdatabaseViews Roles in selected database SQLSERVER:SQLmachineinstanceDatabasesdatabaseRoles Triggers in selected database SQLSERVER:SQLmachineinstanceDatabasesdatabaseTriggers Virtual drive
53 PowerShell and SQLServer Provider
Import-Module WebAdministration Get-Command *-Web* Anything you can do from IIS Manager, you can script it from PowerShell - CRUD on application pools - Start, stop, recycle application pools, set their «bitness» or the .Net framework used - CRUD on virtual directories - Start, stop web sites - Security settings - Start, stop W3S services - … See IISHelpers.psm1 in CCast scripts 54 PowerShell and IIS Provider
Think Puppet for Windows Prevent server configuration drift Separate configuration from implementation Continuous server deployment Manage servers on site or in a cloud What you can do with DSC • Install or remove server roles and features • Manage registry settings • Manage files and directories • Start, stop, and manage processes and services • Manage local groups and user accounts • Install and manage packages such as .msi and .exe • Manage environment variables • Run Windows PowerShell scripts • Fix a configuration that has drifted away from the desired state • Discover the actual configuration state on a given node 55 PowerShell Desired State Configuration
56 PowerShell Desired State Configuration Example
Declarative configuration, using all bells and whistles of PowerShell Separate data from logic: data can be reused for different resources, nodes and configurations Continuous deployment: deploy over and over without breaking anything Only apply diffs in configurations when configurations change Usable on-premise, in public or private cloud Works like a charm with Azure A little bit less so with Amazon 57 Why is DSC so cool?

More Related Content

Power shell training

  • 2. 2
  • 3. In Windows’ world, PowerShell allows to script and automate everything but the kitchen sink Windows Server - Active Directory - Internet Information Server - NLBS, fail over clustering, group policies, backups, scheduling tasks … - HyperV Windows Management & Instrumentation (WMI) SQL Server Exchange Server SharePoint Azure But also outside Windows’ world Amazon AWS PowerShell is an essential tool for sysadmins and devOps 3 PowerShell is Everywhere
  • 4. 4 PowerShell Versions PowerShell 1 PowerShell 2 PowerShell 3 PowerShell 4 PowerShell 5 WXP SP2 WS 2003 Optional on WS 2008 W7 WS 2008 R2 Installable on: WXP SP3 WS 2003 SP3 W8 WS 2012 Installable on: W7 SP1 WS 2008 SP1 WS 2008 R2 SP1 W8.1 WS 2012 R2 Installable on: W7 SP1 WS 2008 R2 SP1 WS 2012 Installable on same platforms as PowerShell 4
  • 5. 5 PowerShell Features PowerShell 1 PowerShell 2 PowerShell 3 PowerShell 4 PowerShell 5 Initial version (2006) New cmdlets Remoting Background jobs Modules Transactions Debugging Eventing Exception handling PowerShell ISE New cmdlets New modules Workflows (WWF) Schedulled jobs WebAccess Remote sessions tolerant to network failures Updatable help Code completion in ISE New cmdlets New modules Desired state configuration (DSC) Enhanced debugging Network diagnostics New cmdlets New modules Support for Chocolatey (aka apt-get for Windows)
  • 6. 6 PowerShell Hosts The good ole’ console (real men use the command line)
  • 8. PowerGUI 8 PowerShell Hosts • Free (brought to you by Dell) • Better debugging than PS ISE • Plugin for Visual Studio
  • 9. 9 PowerShell Hosts Based on their own PowerShell host applications i.e.: they don’t use powershell.exe SQLPS.exe for SQLServer Devenv.exe for Visual Studio
  • 10. Two versions of PowerShell on a 64bit machine - 32Bit: C:WindowsSysWOW64WindowsPowerShellv1.0powershell.exe - 64Bit: C:WindowsSystem32WindowsPowerShellv1.0powershell.exe Might be important to know when you use some PowerShell modules E.g.: you have a 32bit SQLServer installed on your 64bit machine and you want to import the SQLPS module. Wont’ work in PowerShell 64bit, will work like a charm on PowerShell 32bit… 10 Before going further: PowerShell Traps & Pitfalls Yeah, right!
  • 11. How do I know which version of PowerShell I’m running? $PSVersionTable $Host How do I know if I’m running the 64bit or the 32bit version? [IntPtr]::size -eq 8 #64bit [IntPtr]::size -eq 4 #32bit 11 PowerShell Traps & Pitfalls
  • 12. Profiles allow to gather things you use frequently (aliases, modules, functions…) They are loaded when PowerShell starts 4 different profiles - %windir%system32WindowsPowerShellv1.0profile.ps1 This profile applies to all users and shells - %windir%system32WindowsPowerShellv1.0Microsoft.PowerShell_profile.ps1 This profile applies to all users, but only to the Microsoft.PowerShell shell - %UserProfile%My DocumentsWindowsPowerShellprofile.ps1 This profile applies only to the current user, but affects all shells - %UserProfile%My DocumentsWindowsPowerShellMicrosoft.PowerShell_profile.ps1 This profile applies only to the current user and the Microsoft.PowerShell shell 12 PowerShell Profiles
  • 13. One thing you should put in your profile Beware of the formatting gremlins 13 PowerShell Traps & Pitfalls
  • 14. Scripts are good things, scripts are bad things - Consistent and repeatable administration of IT resources but … - PowerShell scripts can do anything in your Windows environment - … and that’s a wide open door for introducing malware in your walls - Users can (and will) execute scripts without really understanding what they are doing PowerShell intends to create a «secure by default» environment for running scripts - The shell makes it difficult for users to run scripts without realizing they are doing so - The default configuration is not convenient, but you can reconfigure execution policies - Multiple security options help you to find a balance between convenience and security 14 PowerShell Security
  • 15. Policy Name Description Restricted (default) Scripts won’t run. Period. RemoteSigned Scripts created locally will run. Those downloaded from Internet won’t unless they are signed by a trusted publisher (use the 'Zone.Identifier' alternate data stream) AllSigned Scripts will only run if they are digitally signed by a trusted publisher Unrestricted Scripts will run regardless of their provenance, signed or not. You are on your own, dude 15 PowerShell Execution Policies • Get-ExecutionPolicy • Set-ExecutionPolicy • Get-Help about_Execution_Policies
  • 16. Two steps process 1. Create a certificate (if you don’t already have one) 2. Sign your script Something like this appears at the end of your script 16 Signing Scripts PowerShell Provider
  • 17. 17 Anatomy of a PowerShell Script cmdlets built-in functions logical constructs
  • 18. PowerShell commands are implented as cmdlets or as built-in functions A cmdlet is a lightweight command implented as a .Net class They are not stand-alone executables (i.e.: they are only available in a PowerShell context) You can very easily create your owns, with a little bit of C# Built-in functions are implemented in PowerShell Tip: How do I get a list of known, globally scoped, functions (builtin/user)? cd function: dir Tip: How do I see the content of a built-in function? ${function:clear-host} 18 Anatomy of a PowerShell Script PowerShell Provider
  • 19. How do I get a list of all known PowerShell commands? Get-Command | more How do I get help for a given command? Get-Help <Command> How do I get help for a specific topic? Get-Help about Example: Get-Help about_Workflows How can I be sure I’m using the latest help available? Update-Help # Of course, you need Internet access… 19 PowerShell Help Will provide a (looong) list of topics for which you can get help: things like debugging, jobs, workflows, parsing, regexs …
  • 20. 20 PowerShell Verb-Noun Conventions All PowerShell cmdlets follow some naming conventions How do I get a list of PowerShell approved verbs and their conventional meaning? Get-Verb These conventions are not strictly mandatory, but it is strongly advised to follow them Commands and variables are case-insensitive High consistency in parameters naming and conventions across all cmdlets Get-Help about_CommonParameters An example: all potentially harmful commands have a –WhatIf parameter del *.txt –WhatIf will list all files that would be deleted executing the command POLA (Principle Of Least Astonishment) The common parameters are a set of cmdlet parameters that you can use with any cmdlet. They are implemented by PowerShell, not by the cmdlet developer, and they are automatically available to any cmdlet.
  • 21. Variable names start with $ ${this variable name is "unusual," but permitted} = "Hello World" Dynamicaly typed $x = "5" What will be the result of $x + 3 ? You can be explicit [int] $x = "5" What will be the result of $x + 3 ? Cast $x = [int] "5" Once a type has been explicitly set, it cannot be changed [int] $x = 3; $x = Get-Date $x = 3; $x = Get-Date  Multiple assignments $a = $b = $c = 1 $Value1, $Value2 = 10,20 21 PowerShell Variables Any .Net type
  • 22. Scope modifiers global, local, script, private Get-Help about_Scopes To explicitly modify a scope, the syntax is $<scope>:<name> $global:xyzzy = 42 $local:foobar = Get-FooBar function private:Hello { Write-Host ‘Hello’ } Or Set-Variable –scope Global –name plugh –value 10 An item you include in a scope is visible in the scope in which it was created and in any child scope, unless you explicitly make it private. You can place variables, aliases, functions in one or more scopes An item that you created within a scope can be changed only in the scope in which it was created, unless you explicitly specify a different scope 22 PowerShell Scopes No $ prefix!
  • 23. How do I know variables defined in a given scope? Get-Variable -scope <scope> How do I list global variables and their values? cd variable: dir Special variables $_ – Contains the current pipeline object, used in script blocks, filters, and the where statement $Args – Contains an array of the parameters passed to a function $Error – Contains objects for which an error occurred while being processed in a cmdlet $Home – Specifies the user’s home directory $PsHome – The directory where the Windows PowerShell is installed Environment variables $env:<variable> (ex.: $env:COMPUTERNAME, $env:Path) 23 PowerShell Variables More on that later
  • 24. Variables are expanded in double-quoted strings Variables are not expanded in single-quoted strings $name = "David" Write-Host "Howdy $name" # Output: Howdy David Write-Host 'Ahoy $name' # Output: Ahoy $name Avoiding expansion in double-quoted strings through escaping Write-Host "Howdy `$name" # Output: Howdy $name Backtick ( ` ) as escaping character Escaping a double quote in a double-quoted string Write-Host "Howdy `"$name`"" # Output: Howdy "David" Some escaped sequences have special meanings `t = TAB `r = carriage return `r`n = carriage return + line feed 24 PowerShell Variables Expansion and Escaping
  • 25. Like in Unix, most of cmdlets can be piped dir –recurse | where { $_.LastWriteTime -gt (Get-Date).AddDays(-5) } | sort Length User functions can be pipe-able too 25 PowerShell Pipeline These commands are aliases
  • 26. Synonyms for cmdlets and functions dir = Get-ChildItem del = Remove-Item where = Where-Object sort = Sort-Object How do I get a list of aliases? Get-Alias How do I get definition for a specific alias? Get-Alias <command> (ex: Get-Alias dir) How do I define my own aliases? Set-Alias (ex: Set-Alias n++ "C:Program Files (x86)Notepad++notepad++.exe") How do I remove an alias Remove-Item alias:<command> (ex: Remove-Item alias:dir) 26 PowerShell Aliases
  • 27. • for($i = 0; $i -le 10; ++$i) { Write-Host "Hello World" } • foreach($i in 0..9) { Write-Host "Hello World" } • $i = 0; do { Write-Host "Hello World"; ++$i } while ($i -le 10) • $i = 0; while ($i -le 10) { Write-Host "Hello World"; ++$i } • break, continue 27 PowerShell Basic Language Constructs: Loops PowerShell Traps & Pitfalls
  • 28. $i = 5; if ($i -gt 3 -and $i -lt 8) { Write-Host "Yepeee" } $a = 5 switch ($a) { 1 {"The color is red."} 2 {"The color is blue."} 3 {"The color is green."} 4 {"The color is yellow."} 5 {"The color is orange."} 6 {"The color is purple."} 7 {"The color is pink."} 8 {"The color is brown."} default {"The color could not be determined."} } 28 PowerShell Basic Language Constructs: Conditional Statements PowerShell Traps & Pitfalls
  • 29. The value of $true is … True The value of $false is … False What is the value of $true -eq $false ? What is the value of $true -eq "False" ? 29 PowerShell Traps & Pitfalls: $true, $false $true $false $true $false Any string of length > 0 Empty string Any number > 0 Any number = 0 Array of length > 1 Array of length 0 Array of length 1 whose element is true Array of length 1 whose element is false A reference to any object $null
  • 30. 30 PowerShell Basic Language Constructs: try/catch/finally back tick to split single command on multiple lines catching specific .Net exceptions One of the common parameters for cmdlets Stop Continue SilentlyContinue Inquire
  • 31. 31 PowerShell Functions Not mandatory to specify a type Alternative (prefered) syntax PowerShell Traps & Pitfalls One of the main sources of errors when you learn Powershell Calling functions with multiple parameters: NO COMMA, NO PARENTHESIS in function calls, unless you are calling .Net native functions (more on that later)
  • 32. Function parameters can be decorated with attributes telling - Their type - If they are mandatory or not - If they have default value - If they can accept values from pipeline - If they are « switch » parameters - Their position and name - … $Args inside a function contains an array with all parameters at call time 32 PowerShell Function Parameters
  • 33. 33 PowerShell Traps & Pitfalls Comma is the array construction operator A comma on indicates a collection of objects bound to one parameter PowerShell tip: use Set-ScrictMode at the beginning of your scripts Checks the following items: • References to uninitialized variables, both directly and from within strings • References to non-existent properties of an object • Calling a function like a method
  • 34. $states = @{"Washington" = "Olympia"; "Oregon" = "Salem"; California = "Sacramento"} $states # Let’s display the content of $states Name Value ---- ----- California Sacramento Washington Olympia Oregon Salem # Let’s add a key/value $states.Add("Alaska", "Fairbanks") $states | Get-Member One of the most usefull and underused function in PowerShell 34 PowerShell Hashtables TypeName: System.Collections.Hashtable Name MemberType Definition ---- ---------- ---------- Add Method void Add(System.Object key, System.Object … Clear Method void Clear(), void IDictionary.Clear() Clone Method System.Object Clone(), System.Object ICloneable.Clone() Contains Method bool Contains(System.Object key), bool … ContainsKey Method bool ContainsKey(System.Object key) ContainsValue Method bool ContainsValue(System.Object value) CopyTo Method void CopyTo(array array, int arrayIndex), … Equals Method bool Equals(System.Object obj) GetEnumerator Method System.Collections.IDictionaryEnumerator GetEnumerator(), … GetHashCode Method int GetHashCode() GetObjectData Method void GetObjectData(System.Runtime.Serialization… GetType Method type GetType() OnDeserialization Method void OnDeserialization(System.Object sender), … Remove Method void Remove(System.Object key), void … ToString Method string ToString() Item ParameterizedProperty System.Object Item(System.Object key) {get;set;} Count Property int Count {get;} IsFixedSize Property bool IsFixedSize {get;} IsReadOnly Property bool IsReadOnly {get;} IsSynchronized Property bool IsSynchronized {get;} Keys Property System.Collections.ICollection Keys {get;} SyncRoot Property System.Object SyncRoot {get;} Values Property System.Collections.ICollection Values {get;}
  • 35. 35 Documenting PowerShell Functions A structured multi-lines comment in function’s header, before the param block HowTo here
  • 37. Assigning PowerShell code to a variable (aka anonymous functions or lambdas) Can be used as parameter to functions $x = { Write-Host "Hello, World!" } $x.GetType() # IsPublic IsSerial Name BaseType # -------- -------- ---- -------- # True False ScriptBlock System.Object $x # What's the content of $x? # Output: Write-Host "Hello, World!" # Let's invoke the script block $x.Invoke() # Output: Hello, World! 37 PowerShell Script Blocks
  • 38. A PowerShell script having .psm1 as its file extension (.ps1 for standard scripts) Gathering reusable functions, variables, aliases… Loaded in your scripts through Import-Module <path to your .psm1 file> -DisableNameChecking –Force You can put that in your profile.ps1 file Functions, variables, aliases you want to make available outside your .psm1 file must be explictly exported At the end of the module file, you typically find Export-ModuleMember -function * # * = all. But can be comma separated function list Export-ModuleMember -variable * 38 PowerShell Modules Avoid warnings if you haven’t followed PowerShell naming conventions (verb-noun) Forces load of your module (usefull when you modify it while writing and debugging your scripts)
  • 39. 39 PowerShell Structured Objects (PSObjects) PowerShell Traps & Pitfalls Use $($object.Field) for expanding structured objects in strings • PowerShell has no concept of a class, so classical inheritance is not an option However, PowerShell’s Adaptive Type System (ATS) gives us great power in implementing prototypal objects, and mixins • Easily persist PSObjects to files through Export-CliXML / Import-CliXML
  • 40. 40 PowerShell and .CSV Files Shortcut for foreach
  • 41. PowerShell is really your friend whent it comes to handle XML files Anything you can do in .Net (xpath, xquery, xslt…), you can do it simpler in PowerShell Can’t explain it all on one slide… Just a small example for changing all connection strings in App.config 41 PowerShell and .XML Files Get-Content normaly returns an array of strings. Here that array is casted to an XML document
  • 42. 42 PowerShell and .JSON Files ConvertFrom-Json ConvertTo-Json Extremely useful with: Invoke-RESTMethod Invoke-WebRequest
  • 43. 43 PowerShell and WebServices This is a COM object … and this is its ComID Don’t forget about Get-Member $IE | Get-Member will produce a list of methods And properties for IE
  • 44. 44 PowerShell and Invoking .Net Classes Add-Type –AssemblyName System.EnterpriseServices is the new PowerShell 3 way. Prefer it when you can.
  • 45. 45 PowerShell and In-line C# Code Calling a static method Calling a standard method requires an instance
  • 46. Connects two copies of PowerShell over the network The «client copy» (where you sit) sends commands to one or more «server copies» (remote machines) Remote machines execute commands locally, and send back resulting objects Relies on PSSession, an object that represents an authenticated connection between two computers $s1 = New-PSSession -ComputerName Server1 –Authentication <Some Authentication> Invoke-Command -Session $s1 -ScriptBlock { <Some PS code> } -AsJob Persists the connection in a variable, persists multiple connections in an array «Persist» does not mean «constantly send traffic»; it reconnects on demand invisibly Easy to setup in Windows domains, a little bit trickier for workgroups 46 PowerShell Remoting
  • 47. 47 PowerShell Remoting • Uses HTTP and HTTPS as the underlying transport, on port 5985 (default) • Communications are handled by Windows Remote Management (WinRM), a service that implements Web Services for Management (aka WS-MAN) • PWA (PowerShell Web Acces in Windows Server 2012) Gives you a PowerShell Console in your web brower • http://powershell.org/wp/ebooks/ Secrets of PowerShell Remoting (and other free e-books)
  • 48. $job = Start-Job -ScriptBlock { Get-Process } Get-job $job.Name Receive-Job $job.Name 48 PowerShell and Background Jobs Your background job Get-Help about_Jobs Get-Help about_Job_Details Get-Help about_Remote_Jobs
  • 49. PowerShell 3.0 or later Integration with Windows Workflow Foundation Each activity of the workflow can run in its own runspace, possibly remotely Variables that are created at the top level of the entire workflow are available throughout the workflow Workflows can be designed through the Visual Studio Workflow Designer Get-Help about_Workflow_Common_Parameters Get-Help about_Workflows 49 PowerShell and Workflows
  • 51. «Mount» hierarchical structures as if they were a virtual file system Get-Help about_Providers Often used by Microsoft’s PowerShell modules to abstract and ease access to their own software (Active Directory, Exchange, IIS, SQLServer, SharePoint…) You can easily implement your own (XT3 PowerShell Provider, anyone?) 51 PowerShell Providers
  • 52. Import-Module sqlps -DisableNameChecking Anything you can do from SQL Enterprise manager, you can script it from PowerShell 52 PowerShell and SQLServer Provider SQL Server data store root SQLSERVER: Network root SQLSERVER:SQL Instances on selected machine SQLSERVER:SQLmachine Top-level objects in selected instance SQLSERVER:SQLmachineinstance Databases in selected instance SQLSERVER:SQLmachineinstanceDatabases Top-level objects in selected database SQLSERVER:SQLmachineinstanceDatabasesdatabase Tables in selected database SQLSERVER:SQLmachineinstanceDatabasesdatabaseTables Views in selected database SQLSERVER:SQLmachineinstanceDatabasesdatabaseViews Roles in selected database SQLSERVER:SQLmachineinstanceDatabasesdatabaseRoles Triggers in selected database SQLSERVER:SQLmachineinstanceDatabasesdatabaseTriggers Virtual drive
  • 54. Import-Module WebAdministration Get-Command *-Web* Anything you can do from IIS Manager, you can script it from PowerShell - CRUD on application pools - Start, stop, recycle application pools, set their «bitness» or the .Net framework used - CRUD on virtual directories - Start, stop web sites - Security settings - Start, stop W3S services - … See IISHelpers.psm1 in CCast scripts 54 PowerShell and IIS Provider
  • 55. Think Puppet for Windows Prevent server configuration drift Separate configuration from implementation Continuous server deployment Manage servers on site or in a cloud What you can do with DSC • Install or remove server roles and features • Manage registry settings • Manage files and directories • Start, stop, and manage processes and services • Manage local groups and user accounts • Install and manage packages such as .msi and .exe • Manage environment variables • Run Windows PowerShell scripts • Fix a configuration that has drifted away from the desired state • Discover the actual configuration state on a given node 55 PowerShell Desired State Configuration
  • 56. 56 PowerShell Desired State Configuration Example
  • 57. Declarative configuration, using all bells and whistles of PowerShell Separate data from logic: data can be reused for different resources, nodes and configurations Continuous deployment: deploy over and over without breaking anything Only apply diffs in configurations when configurations change Usable on-premise, in public or private cloud Works like a charm with Azure A little bit less so with Amazon 57 Why is DSC so cool?