book

Mastering PowerShell Scripting - Fifth Edition

Name: Mastering PowerShell Scripting - Fifth Edition
Author: Chris Dent
ISBN: 9781805120278

by Chris Dent

May 2024

Intermediate to advanced

826 pages

18h 13m

English

Packt Publishing

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Preface
Introduction to PowerShell
Technical requirementsWhat is PowerShell?The command linePowerShell editorsGetting helpUpdatable helpThe Get-Help commandSyntaxExamplesParameterDetailed and Full switchesSave-HelpUpdate-HelpAbout_* help filesCommand naming and discoveryVerbsNounsFinding commandsAliasesAbout profile scriptsParameters, values, and parameter setsParametersOptional parametersOptional positional parametersMandatory parametersMandatory positional parametersSwitch parametersParameter valuesParameter setsCommon parametersConfirm and WhatIfConfirm and ConfirmPreferenceWhatIf and WhatIfPreferenceForce parameterPassThru parameterIntroduction to providersDrives and providersIntroduction to splattingSplatting to avoid long linesConditional use of parametersSplatting to avoid repetitionSplatting and positional parametersParser modesExperimental featuresSummary
Modules
Introducing modulesThe Get-Module commandThe Import-Module commandThe Remove-Module commandPSModulePath in PowerShellModule contentUsing Windows PowerShell modules in PowerShell 7Finding and installing modulesWhat is the PowerShell Gallery?The Find-Module commandThe Install-Module commandThe Update-Module commandThe Save-Module commandMicrosoft.PowerShell.PSResourceGetRepositoriesVersion rangesPowerShell repositoriesCreating an SMB repositoryNuGet repositoriesAbout snap-insSummary
Variables, Arrays, and Hashtables
Naming and creating variablesProvider variablesVariables in stringsVariable typesAssignment with types on the rightAssignment with types on the leftValue and reference typesType conversionVariable commandsGet-VariableNew-VariableSet-VariableRemove-VariableClear-VariableVariable providerVariable scopeAccessing variablesScope modifiersNumeric scopesPrivate variablesAbout arraysArray typeCreation by assignmentCreating an arrayArrays with a typeAdding elements to an arrayList and ArrayListSelecting elements from an arrayChanging element values in an arrayRemoving elementsRemoving elements by indexFilling variables from arraysMulti-dimensional and jagged arraysAbout hashtablesCreating a HashtableAdding, changing, and removing keysUsing a hashtable to filterEnumerating a HashtableAbout OrderedSummary
Working with Objects in PowerShell
PipelinesStandard outputNon-standard outputThe Object pipelineMembersThe Get-Member commandAccessing object propertiesAccess modifiersUsing methodsReturn types and argument typesCreating and modifying objectsUsing PSCustomObjectThe New-Object commandThe Add-Member commandAdd-Member and custom objectsEnumerating and filteringThe ForEach-Object commandBegin and End parametersThe Parallel parameterThe MemberName parameterThe Where-Object commandSelecting and sortingThe Select-Object commandCalculated propertiesThe ExpandProperty parameterThe Unique parameterProperty setsThe Sort-Object commandThe Unique parameterGrouping and measuringThe Group-Object commandThe Measure-Object commandComparingImporting, exporting, and convertingThe Export-Csv commandThe Import-Csv commandExport-Clixml and Import-ClixmlThe Tee-Object commandFormattingFormatting and exportingThe Format-Table commandThe Format-List commandSelect-Object, Write-Host, and inline outputFormat-only propertiesSummary
Operators
Precedence, grouping, and sub-expressionsOperator precedenceGroupingSub-expression operatorArray sub-expression operatorUnary, binary, and ternary operatorsAbout the ternary operatorArithmetic operatorsAddition operatorSubtraction operatorMultiplication operatorDivision operatorRemainder operatorIncrement and decrement operatorsComparison operatorseq and nelike and notlikeGreater than and less thanCase sensitivityComparison operators and arraysComparisons to nullcontains and inRegular expression-based operatorsmatch and notmatchreplacesplitLogical operatorsandornotxor (eXclusive OR)Bitwise operatorsband (bitwise AND)bor (bitwise OR)bxor (bitwise eXclusive OR)bnot (bitwise NOT)shl and shr (shift left and right operators)Assignment operatorsAssign, add and assign, and subtract and assignMultiply and assign, divide and assign, and modulus and assignStatements can be assigned to a variableAssignment and other operatorsType operatorsasis and isnotRedirection operatorsAbout Write-HostRedirection to a filePowerShell and default file encodingRedirecting streams to standard outputOnly stdoutRedirection to nullOther operatorsCommaIndexRangeCallFormatjoinNull coalescingNull coalescing assignmentNull conditionalPipeline chainBackgroundSummary
Conditional Statements and Loops
if, else, and elseifAssignment within if statementsImplicit Booleanswitch statementsswitch statements and arraysswitch statements and filesWildcard and Regex parametersScript block casesswitch statements and enumsswitch, break, and continueLoopsforeach loopforeach keyword and foreach aliasfor loopdo-until and do-while loopswhile loopLoops, break, and continuebreak and continue outside loopsLoops and labelsLoops, queues, and stacksSummary
Working with .NET
AssembliesAbout the GACTypesType descriptions are objects in PowerShellEnumerationsClassesNamespacesThe using keywordUsing namespacesUsing assembliesType acceleratorsAbout PSCustomObject and OrderedMembersConstructorsPropertiesMethodsFluent interfacesStatic methodsAbout the new() methodStatic propertiesReflection in PowerShellThe TypeAccelerators typeThe ArgumentTypeConverterAttribute typeAbout genericsGeneric classesGeneric methodsSummaryOnline ChapterStrings, Numbers, and Dates (Online Chapter)Regular Expressions (Online Chapter)
Files, Folders, and the Registry
Working with providersNavigatingGetting itemsDrivesItemsPaths and .NETTesting for existing itemsTesting filesystem pathsTesting registry pathsTesting path typeCreating itemsReading and writing contentReading and writing in a pipelineReading all contentWriting contentAbout text file encodingTemporary filesRemoving itemsInvoking itemsItem propertiesProperties and the filesystemAdding and removing file attributesRegistry valuesRegistry values and environment variablesSearching for itemsWindows permissionsAccess and auditRule protectionInheritance and propagation flagsRemoving ACEsCopying lists and entriesAdding ACEsFilesystem rightsRegistry rightsNumeric values in the ACLOwnershipTransactionsFile catalog commandsAbout hashingNew-FileCatalogTest-FileCatalogSummary
Windows Management Instrumentation
Working with WMIWMI classesWMI commandsCIM commandsGetting instancesGetting classesCalling methodsCreating instancesRemoving instancesWorking with CIM sessionsAssociated classesThe WMI Query LanguageUnderstanding SELECT, WHERE, and FROMEscape sequences and wildcardsComparison operatorsWQL filters and datesLogic operatorsQuoting valuesAssociated classesWMI object pathsUsing ASSOCIATORS OFWMI type acceleratorsGetting instancesWorking with datesGetting classesCalling methodsCreating instancesAssociated classesPermissionsSharing permissionsCreating a shared directoryGetting a security descriptorAdding an access control entrySetting the security descriptorWMI permissionsGetting a security descriptorThe access maskWMI and SDDLSummary

Working with HTML, XML, and JSON
ConvertTo-HtmlMultiple tablesAdding styleConvertTo-Html and Send-MailMessageWindows PowerShell and ConvertTo-HtmlModifying HTML contentXML commandsAbout XMLElements and attributesNamespacesSchemasSelect-XmlSelect-Xml and namespacesConvertTo-XmlSystem.XmlThe XML type acceleratorXPath and XmlDocumentSelectNodes and XPathNodeListWorking with namespacesCreating XML documentsModifying element and attribute valuesAdding elementsRemoving elements and attributesCopying nodes between documentsSchema validationInferring a schemaSystem.Xml.LinqOpening documentsSelecting nodesCreating documentsWorking with namespacesModifying element and attribute valuesAdding nodesRemoving nodesSchema validationJSONConvertTo-JsonEnumsAsStringsAsArrayEscapeHandlingConvertFrom-JsonAsHashtableNoEnumerateTest-JsonSummary
Web Requests and Web Services
Technical requirementsWeb requestsHTTP methodsUsing Invoke-WebRequestAbout parsing web pagesDownloading filesUsing the HEAD methodHTTPSSecurity protocolsCertificate validationWindows PowerShell and certificate validationCapturing SSL errorsWorking with RESTSimple requestsUsing basic authenticationRequests with argumentsWorking with pagingOAuthCreating an applicationGetting an authorization codeImplementing an HTTP listenerRequesting an access tokenUsing a tokenWorking with SOAPFinding a SOAP serviceSOAP in Windows PowerShellNew-WebServiceProxyMethodsMethods and enumerationsMethods and SOAP objectsOverlapping servicesSOAP in PowerShell 7Getting the WSDL documentDiscovering methods and enumerationsRunning methodsSummary
Remoting and Remote Management
Technical requirementsExecuting remote commandsEnter-PSSessionInvoke-CommandParallel executionCatching remoting failuresLocal functions and remote sessionsUsing ArgumentListThe using scope modifierPS SessionsNew-PSSession and Get-PSSessionDisconnected sessionsImport-PSSessionExport-PSSessionCopying items between sessionsWS-ManagementEnabling and configuring remotingThe WSMan driveRemoting and SSLUser Account ControlTrusted hostsRemoting on LinuxRemoting over SSHConnecting from Windows to LinuxConnecting from Linux to WindowsThe double-hop problemCredSSPPassing credentialsCIM sessionsGet-CimSessionUsing CIM sessionsJust Enough AdministrationSession configurationRole capabilitiesSummary
Asynchronous Processing
Working with jobsStart-Job, Get-Job, and Remove-JobReceive-JobWait-JobJobs and the using scope modifierThe background operatorThe ThreadJob moduleBatching jobsReacting to eventsThe Register-ObjectEvent and *-Event commandsAction, Event, EventArgs, and MessageData parametersGet-EventSubscriber and Unregister-EventUsing runspaces and runspace poolsCreating a PowerShell instanceThe Invoke and BeginInvoke methodsAbout Streams and InvocationStateInfoRunning multiple instancesUsing the RunspacePool objectAbout the InitialSessionState objectAdding modules and snap-insAdding variablesAdding functionsUsing the InitialSessionState and RunspacePool objectsUsing thread-safe objectsManaging concurrent accessSummary
Graphical User Interfaces
About Windows Presentation Foundation (WPF)Designing a UIAbout XAMLDisplaying the UILayoutUsing the Grid controlUsing the StackPanel controlUsing the DockPanel controlAbout Margin and PaddingNaming and locating controlsHandling eventsButtons and the Click eventComboBox and SelectionChangedAdding elements programmaticallySorting a ListViewResponsive interfacesImport-Xaml and runspace supportErrors in the backgroundUsing the DispatcherScriptBlock runspace affinityUsing the Action delegateUsing the Func delegateSummary
Scripts, Functions, and Script Blocks
About styleCapabilities of scripts, functions, and script blocksScripts and using statementsScripts and the Requires statementNesting functionsScript blocks and closuresParameters and the param blockParameter typesDefault valuesCross-referencing parametersThe CmdletBinding attributeCommon parametersCmdletBinding propertiesShouldProcess and ShouldContinueShouldProcessShouldContinueThe Alias attributebegin, process, end, and cleanbeginprocessendcleanNamed blocks and returnManaging outputThe Out-Null commandAssigning to nullRedirecting to nullCasting to voidWorking with long linesLine break after a pipeLine break after an operatorUsing the array sub-expression operator to break up linesComment-based helpOutput helpParameter helpExamplesSummary
Parameters, Validation, and Dynamic Parameters
The Parameter attributePosition and positional bindingThe DontShow propertyThe ValueFromRemainingArguments propertyThe HelpMessage propertyValidating inputThe PSTypeName attributeValidation attributesThe ValidateNotNull attributeThe ValidateNotNullOrEmpty attributeThe ValidateNotNullOrWhitespace attributeThe ValidateCount attributeThe ValidateLength attributeThe ValidatePattern attributeThe ValidateRange attributeThe ValidateScript attributeThe ValidateSet attributeThe ValidateDrive attributeThe ValidateUserDrive attributeThe Allow attributesThe AllowNull attributeThe AllowEmptyString attributeThe AllowEmptyCollection attributePSReference parametersPipeline inputAbout ValueFromPipelineAccepting null inputInput object typesUsing ValueFromPipeline for multiple parametersAbout ValueFromPipelineByPropertyNameValueFromPipelineByPropertyName and parameter aliasesDefining parameter setsArgument completersThe ArgumentCompleter attributeUsing Register-ArgumentCompleterAbout CompletionResultNon-literal valuesListing registered argument completersDynamic parametersCreating a RuntimeDefinedParameter objectUsing RuntimeDefinedParameterDictionaryUsing dynamic parametersPSBoundParametersRuntimeDefinedParameterDictionaryConditional parametersSummary
Classes and Enumerations
Defining an enumerationEnum and underlying typesAutomatic value assignmentEnum or ValidateSetThe Flags attributeUsing enumerations to convert a valueCreating a classPropertiesConstructorsMethodsThe Hidden modifierThe static modifierInheritanceConstructors and inheritanceCalling methods in a parent classWorking with interfacesImplementing IComparableImplementing IEquatableSupporting castingClasses and runspace affinityTransformation, validation, and completionArgument transformation attribute classesValidation attribute classesValidateArgumentsAttributeValidateEnumeratedArgumentsAttributeValidateSet value generatorArgument completersIArgumentCompleterIArgumentCompleterFactoryClasses and Microsoft Desired State ConfigurationImplementing GetImplementing SetImplementing TestUsing the resourceSummaryOnline ChapterBuilding Modules (Online Chapter)
Testing
Technical requirementsStatic analysisPSScriptAnalyzerConfigurable rulesSuppressing rulesUsing ASTVisualizing the ASTSearching the ASTTokenizerCustom script analyzer rulesCreating a custom ruleAST-based rulesToken-based rulesTesting with PesterTesting methodologiesWhat to testDescribing testsAbout the Describe and Context keywordsAbout the It keywordShould and assertionsTesting for errorsIteration with PesterUsing the ForEach parameterForEach with Describe and ContextConditional testingUsing Set-ItResultUsing SkipPester phasesBefore and After blocksMocking commandsParameter variablesParameter filteringOverriding mocksMocking non-local commandsMocking objectsAdding methods to PSCustomObjectDisarming .NET typesMocking CIM objectsInModuleScopePester in scriptsSummary
Error Handling
Error typesTerminating errorsNon-terminating errorsError actionsAbout Get-ErrorRaising errorsError recordsRaising non-terminating errorsUsing the WriteError methodRaising terminating errorsUsing the ThrowTerminatingError methodCatching errorsErrorVariabletry, catch, and finallyRethrowing errorsInconsistent error handlingthrow and ErrorActionTerminating errors in child scopesNesting try, catch, and finallyAbout trapUsing traptrap, scope, and continueSummary
Debugging
Common problemsDash charactersOperator usageAssignment instead of equality-or instead of -andNegated array comparisonsUse of named blocksCode outside of a named blockPipeline without processProblems with variablesAbout strict modeVariables and typesTypes and reserved variablesDebugging in the consoleSetting a command breakpointUsing variable breakpointsSetting a line breakpointDebugging in Visual Studio CodeUsing the debuggerViewing CALL STACKUsing launch configurationsDebugging modulesUsing WATCHDebugging other PowerShell processesSummary
Other Books You May Enjoy
Index

Content preview from Mastering PowerShell Scripting - Fifth Edition

3 Variables, Arrays, and Hashtables

A variable in a programming language is used to give a name to a piece of information or data. A variable can be used and re-used in the console, script, or function, or any other piece of code.

A variable may be of any .NET type or object instance. It may contain a string such as "Hello World", an integer such as 42, a decimal such as 3.141, an array, a hashtable, a ScriptBlock, and so on. Everything a variable might refer to is an object when used in PowerShell.

This chapter covers the following topics:

Naming and creating variables
Variables in strings
Variable types
Variable commands
Variable providers
Variable scope
About arrays
About hashtables
About Ordered

A variable must be given a name when it ...

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Mastering PowerShell Scripting - Fourth Edition

Publisher Resources

ISBN: 9781805120278

Cloud Computing

Data Engineering

Data Science

AI & ML

Programming Languages

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IT/Ops

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Business

Soft Skills

Mastering PowerShell Scripting - Fifth Edition

by Chris Dent

3

Variables, Arrays, and Hashtables

Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.