PowerShell

PowerShell is a shell program developed by Microsoft for task automation and configuration management. As is typical for a shell, it provides a command-line interpreter for interactive use and a script interpreter for automation via a language defined for it. Originally only for Windows, known as Windows PowerShell, it was made open-source and cross-platform on August 18, 2016, with the introduction of PowerShell Core. The former is built on the .NET Framework and the latter on .NET (previously .NET Core). PowerShell is bundled with current versions of Windows and can be installed on macOS and Linux. Since Windows 10 build 14971, PowerShell replaced Command Prompt as the default command shell exposed by File Explorer. In PowerShell, administrative tasks are generally performed via cmdlets (pronounced command-lets), which are specialized .NET classes implementing a particular operation. These work by accessing data in different data stores, like the file system or Windows Registry, which are made available to PowerShell via providers. Third-party developers can add cmdlets and providers to PowerShell. Cmdlets may be used by scripts, which may in turn be packaged into modules. Cmdlets work in tandem with the .NET API.…

PowerShell is a shell program developed by Microsoft for task automation and configuration management. As is typical for a shell, it provides a command-line interpreter for interactive use and a script interpreter for automation via a language defined for it. Originally only for Windows, known as Windows PowerShell, it was made open-source and cross-platform on August 18, 2016, with the introduction of PowerShell Core. The former is built on the .NET Framework and the latter on .NET (previously .NET Core). PowerShell is bundled with current versions of Windows and can be installed on macOS and Linux. Since Windows 10 build 14971, PowerShell replaced Command Prompt as the default command shell exposed by File Explorer. In PowerShell, administrative tasks are generally performed via cmdlets (pronounced command-lets), which are specialized .NET classes implementing a particular operation. These work by accessing data in different data stores, like the file system or Windows Registry, which are made available to PowerShell via providers. Third-party developers can add cmdlets and providers to PowerShell. Cmdlets may be used by scripts, which may in turn be packaged into modules. Cmdlets work in tandem with the .NET API. PowerShell's support for .NET Remoting, WS-Management, CIM, and SSH enables administrators to perform administrative tasks on both local and remote Windows systems. PowerShell also provides a hosting API with which the PowerShell runtime can be embedded inside other applications. These applications can then use PowerShell functionality to implement certain operations, including those exposed via the graphical interface. This capability has been used by Microsoft Exchange Server 2007 to expose its management functionality as PowerShell cmdlets and providers and implement the graphical management tools as PowerShell hosts which invoke the necessary cmdlets. Other Microsoft applications including Microsoft SQL Server 2008 also expose their management interface via PowerShell cmdlets. PowerShell includes its own extensive, console-based help (similar to man pages in Unix shells) accessible via the Get-Help cmdlet. Updated local help contents can be retrieved from the Internet via the Update-Help cmdlet. Alternatively, help from the web can be acquired on a case-by-case basis via the -online switch to Get-Help . ===Philosophy=== A key design goal for PowerShell was to leverage the large number of APIs that already existed in Windows, Windows Management Instrumentation, .NET Framework, and other software. PowerShell cmdlets generally wrap and expose existing functionality instead of implementing new functionality. The intent was to provide an administrator-friendly, more-consistent interface between administrators and a wide range of underlying functionality. With PowerShell, an administrator doesn't need to know .NET, WMI, or low-level API coding, and can instead focus on using the cmdlets exposed by PowerShell. In this regard, PowerShell creates little new functionality, instead focusing on making existing functionality more accessible to a particular audience. function name ([Type]$Param1, [Type]$Param2) { # Instructions } However, PowerShell allows for advanced functions that support named parameters, positional parameters, switch parameters and dynamic parameters. function Verb-Noun { param ( # Definition of static parameters ) dynamicparam { # Definition of dynamic parameters } begin { # Set of instruction to run at the start of the pipeline } process { # Main instruction sets, ran for each item in the pipeline } end { # Set of instruction to run at the end of the pipeline } } The defined function is invoked in either of the following forms: name value1 value2 Verb-Noun -Param1 value1 -Param2 value2 PowerShell allows any static .NET methods to be called by providing their namespaces enclosed in brackets ( [] ), and then using a pair of colons ( :: ) to indicate the static method. For example: [Console]::WriteLine("PowerShell") There are dozens of ways to create objects in PowerShell. Once created, one can access the properties and instance methods of an object using the . notation. PowerShell accepts strings, both raw and escaped. A string enclosed between single quotation marks is a raw string while a string enclosed between double quotation marks is an escaped string. PowerShell treats straight and curly quotes as equivalent. The following list of special characters is supported by PowerShell: For error handling, PowerShell provides a .NET-based exception-handling mechanism. In case of errors, objects containing information about the error ( Exception object) are thrown, which are caught using the try ... catch construct (although a trap construct is supported as well). PowerShell can be configured to silently resume execution, without actually throwing the exception; this can be done either on a single command, a single session or perpetually. Scripts written using PowerShell can be made to persist across sessions in either a .ps1 file or a .psm1 file (the latter is used to implement a module). Later, either the entire script or individual functions in the script can be used. Scripts and functions operate analogously with cmdlets, in that they can be used as commands in pipelines, and parameters can be bound to them. Pipeline objects can be passed between functions, scripts, and cmdlets seamlessly. To prevent unintentional running of scripts, script execution is disabled by default and must be enabled explicitly. Enabling of scripts can be performed either at system, user or session level. PowerShell scripts can be signed to verify their integrity, and are subject to Code Access Security. The PowerShell language supports binary prefix notation similar to the scientific notation supported by many programming languages in the C-family. The ??= operator for null coalescing assignment Cross-platform Invoke-DscResource (experimental) Return of the Out-GridView cmdlet Return of the -ShowWindow switch for the Get-Help == Filename extensions == Windows Management Framework

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