PowerShell is a task automation and configuration management program from Microsoft, consisting of a command-line shell and the associated scripting language.

[10][11] In PowerShell, administrative tasks are generally performed via cmdlets (pronounced command-lets), which are specialized .NET classes implementing a particular operation.

[15] PowerShell includes its own extensive, console-based help (similar to man pages in Unix shells) accessible via the Get-Help cmdlet.

Both environments support a few basic internal commands and a primitive scripting language (batch files), which can be used to automate various tasks.

However, they cannot automate all facets of Windows graphical user interface (GUI) because command-line equivalents of operations are limited and the scripting language is elementary.

Its shortcomings are: its documentation is not very accessible, and it quickly gained a reputation as a system vulnerability vector after several high-profile computer viruses exploited weaknesses in its security provisions.

Different versions of Windows provided various special-purpose command-line interpreters (such as netsh and WMIC) with their own command sets but they were not interoperable.

At the time, Intel CPU development was accomplished on Sun Microsystems computers which ran Solaris (a Unix variant) on RISC-architecture CPUs.

The ideas behind it were published in August 2002 in a white paper called the "Monad Manifesto" by its chief architect, Jeffrey Snover.

[22] In an October 2009 issue of TechNet Magazine, Microsoft called proficiency with PowerShell "the single most important skill a Windows administrator will need in the coming years".

[24] On August 18, 2016, Microsoft announced[25] that they had made PowerShell open-source and cross-platform with support for Windows, macOS, CentOS and Ubuntu.

For example, it enables the creation of different views of objects by exposing only a subset of the data fields, properties, and methods, as well as specifying custom formatting and sorting behavior.

[36] These base classes specify certain methods – BeginProcessing(), ProcessRecord() and EndProcessing() – which the cmdlet's implementation overrides to provide the functionality.

In addition, PowerShell makes certain APIs available, such as WriteObject(), which is used to access PowerShell-specific functionality, such as writing resultant objects to the pipeline.

Windows PowerShell ships with providers for the file system, registry, the certificate store, as well as the namespaces for command aliases, variables, and functions.

Other applications can register cmdlets with PowerShell, thus allowing it to manage them, and, if they enclose any datastore (such as a database), they can add specific providers as well.

Using objects and executing stages within the PowerShell runtime eliminates the need to serialize data structures, or to extract them by explicitly parsing text output.

In addition, PowerShell allows formatting definitions to be specified, so the text representation of objects can be customized by choosing which data elements to display, and in what manner.

However, in order to maintain backward compatibility, if an external executable is used in a pipeline, it receives a text stream representing the object, instead of directly integrating with the PowerShell type system.

[52][53][54] Windows PowerShell includes a dynamically typed scripting language which can implement complex operations using cmdlets imperatively.

The scripting language supports variables, functions, branching (if-then-else), loops (while, do, for, and foreach), structured error/exception handling and closures/lambda expressions,[55] as well as integration with .NET.

PowerShell provides special variables, such as $args, which is an array of all the command-line arguments passed to a function from the command line, and $_, which refers to the current object in the pipeline.

The PowerShell scripting language also evaluates arithmetic expressions entered on the command line immediately, and it parses common abbreviations, such as GB, MB, and KB.

Initially using the code name "Monad", PowerShell was first shown publicly at the Professional Developers Conference in October 2003 in Los Angeles.

[81][82] PowerShell 3.0 is part of a larger package, Windows Management Framework 3.0 (WMF3), which also contains the WinRM service to support remoting.

An early community technology preview 2 (CTP 2) version of Windows Management Framework 3.0 was released on December 2, 2011.

The following table contains a selection of the cmdlets that ship with PowerShell, noting similar commands in other well-known command-line interpreters.

Many of these similar commands come out-of-the-box defined as aliases within PowerShell, making it easy for people familiar with other common shells to start working.

Notes A project named Pash, a pun on the widely known "bash" Unix shell, has been an open-source and cross-platform reimplementation of PowerShell via the Mono framework.

Pash development stalled in 2008, was restarted on GitHub in 2012,[150] and finally ceased in 2016 when PowerShell was officially made open-source and cross-platform.