Windows PowerShell

Windows PowerShell

Paradigm	Multi-paradigm: Imperative, pipeline, object-oriented, functional and reflective
Designed by	Jeffrey Snover, Bruce Payette, James Truher (et al.)
Developer	Microsoft
First appeared	November 14, 2006 (2006-11-14)
Stable release	5.0 / July 29, 2015 (2015-07-29)
Typing discipline	Strong, safe, implicit and dynamic
Platform	.NET Framework
OS	Windows XP and later
License	Proprietary software; a component of Microsoft Windows
Filename extensions	.ps1 (Script) .ps1xml (XML Document) .psc1 (Console File) .psd1 (Data File) .psm1 (Script Module) .pssc (Session Configuration File) .cdxml (Cmdlet Definition XML Document)
Website	{{#property:P856}}
Influenced by
Ksh, Perl, C#, CL, DCL, SQL, Tcl, Tk, Chef, Puppet

Windows PowerShell is a task automation and configuration management framework from Microsoft, consisting of a command-line shell and associated scripting language built on the .NET Framework. PowerShell provides full access to COM and WMI, enabling administrators to perform administrative tasks on both local and remote Windows systems as well as WS-Management and CIM enabling management of remote Linux systems and network devices.

In PowerShell, administrative tasks are generally performed by cmdlets (pronounced command-lets), which are specialized .NET classes implementing a particular operation. Sets of cmdlets may be combined into scripts, executables (which are standalone applications), or by instantiating regular .NET classes (or WMI/COM Objects). These work by accessing data in different data stores, like the file system or registry, which are made available to the PowerShell runtime via Windows PowerShell providers.

Windows PowerShell also provides a hosting API with which the Windows PowerShell runtime can be embedded inside other applications. These applications can then use Windows 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. With PowerShell, graphical interface-based management applications on Windows are layered on top of Windows PowerShell. A PowerShell scripting interface for Windows products is mandated by Microsoft's Common Engineering Criteria.

Windows PowerShell includes its own extensive, console-based help, similar to man pages in Unix shells, via the Get-Help cmdlet. Local help contents can be retrieved from the Internet via Update-Help cmdlet. Alternatively, help from the web can acquired on a case-by-case basis via the -online switch to Get-Help.

Background

Every released version of Microsoft DOS and Microsoft Windows for personal computers has included a command-line interface tool (shell). These are COMMAND.COM (in installations relying on MS-DOS, including Windows 9x) and cmd.exe (in Windows NT family operating systems). The shell is a command line interpreter that supports a few basic commands. For other purposes, a separate console application must be invoked from the shell. The shell also includes a scripting language (batch files), which can be used to automate various tasks. However, the shell cannot be used to automate all facets of GUI functionality, in part because command-line equivalents of operations exposed via the graphical interface are limited, and the scripting language is elementary and does not allow the creation of complex scripts. In Windows Server 2003, the situation was improved, but scripting support was still considered unsatisfactory.

Microsoft attempted to address some of these shortcomings by introducing the Windows Script Host in 1998 with Windows 98, and its command-line based host: cscript.exe. It integrates with the Active Script engine and allows scripts to be written in compatible languages, such as JScript and VBScript, leveraging the APIs exposed by applications via COM. However, it has its own deficiencies: it is not integrated with the shell, 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. None of them were integrated with the command shell; nor were they interoperable.

By 2002 Microsoft had started to develop a new approach to command line management, including a shell called Monad (also known as Microsoft Shell or MSH). The shell and the ideas behind it were published in August 2002 in a white paper entitled Monad Manifesto. Monad was to be a new extensible command shell with a fresh design that would be capable of automating a full range of core administrative tasks. Microsoft first showed off Monad at the Professional Development Conference in Los Angeles in September 2003. A private beta program began a few months later which eventually led to a public beta program.

Microsoft published the first Monad public beta release on June 17, 2005, Beta 2 on September 11, 2005, and Beta 3 on January 10, 2006. Not much later, on April 25, 2006 Microsoft formally announced that Monad had been renamed Windows PowerShell, positioning it as a significant part of their management technology offerings. Release Candidate 1 of PowerShell was released at the same time. A significant aspect of both the name change and the RC was that this was now a component of Windows, and not an add-on product.

Release Candidate 2 of PowerShell version 1 was released on September 26, 2006 with final Release to the web (RTW) on November 14, 2006 and announced at TechEd Barcelona. PowerShell for earlier versions of Windows was released on January 30, 2007.

PowerShell v2.0 development began before PowerShell v1.0 shipped. During the development, Microsoft shipped three community technology preview (CTP). Microsoft made these releases available to the public. The last CTP release of Windows PowerShell v2.0 was made available in December 2008.

PowerShell v2.0 was completed and released to manufacturing in August 2009, as an integral part of Windows 7 and Windows Server 2008 R2. Versions of PowerShell for Windows XP, Windows Server 2003, Windows Vista and Windows Server 2008 were released in October 2009 and are available for download for both 32-bit and 64-bit platforms.

Design

Windows PowerShell can execute four kinds of named commands:

• cmdlets, which are .NET Framework programs designed to interact with PowerShell
• PowerShell scripts (files suffixed by .ps1)
• PowerShell functions
• standalone executable programs

If a command is a standalone executable program, PowerShell.exe launches it in a separate process; if it is a cmdlet, it is executed in the PowerShell process. PowerShell provides an interactive command line interface, wherein the commands can be entered and their output displayed. The user interface, based on the Win32 console, offers customizable tab completion. PowerShell enables the creation of aliases for cmdlets, which are textually translated by PowerShell into invocations of the original commands. PowerShell supports both named and positional parameters for commands. In executing a cmdlet, the job of binding the argument value to the parameter is done by PowerShell itself, but for external executables, arguments are parsed by the external executable independently of PowerShell interpretation.

The PowerShell Extended Type System (ETS) is based on the .NET type system, but with extended semantics (for example, propertySets and third-party extensibility). 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. These views are mapped to the original object using XML-based configuration files.

Cmdlets

Cmdlets are specialized commands in the PowerShell environment that implement specific functions. These are the native commands in the PowerShell stack. Cmdlets follow a Verb-Noun naming pattern, such as Get-ChildItem, helping to make them self-descriptive. Cmdlets output their results as objects, or collections thereof (including arrays), and can optionally receive input in that form, making them suitable for use as recipients in a pipeline. But whereas PowerShell allows arrays and other collections of objects to be written to the pipeline, cmdlets always process objects individually. For collections of objects, PowerShell invokes the cmdlet on each object in the collection, in sequence.

Cmdlets are specialized .NET classes, which the PowerShell runtime instantiates and invokes when they are run. Cmdlets derive either from Cmdlet or from PSCmdlet, the latter being used when the cmdlet needs to interact with the PowerShell runtime. These base classes specify certain methods - BeginProcessing(), ProcessRecord() and EndProcessing() – which the cmdlet's implementation overrides to provide the functionality. Whenever a cmdlet is run, these methods are invoked by PowerShell in sequence, with ProcessRecord() being called if it receives pipeline input. If a collection of objects is piped, the method is invoked for each object in the collection. The class implementing the Cmdlet must have one .NET attribute - CmdletAttribute – which specifies the verb and the noun that make up the name of the cmdlet. Common verbs are provided as an enum.>

If a cmdlet receives either pipeline input or command-line parameter input, there must be a corresponding property in the class, with a mutator implementation. PowerShell invokes the mutator with the parameter value or pipeline input, which is saved by the mutator implementation in class variables. These values are then referred to by the methods which implement the functionality. Properties that map to command-line parameters are marked by ParameterAttribute and are set before the call to BeginProcessing(). Those which map to pipeline input are also flanked by ParameterAttribute, but with the ValueFromPipeline attribute parameter set.

The implementation of these cmdlet classes can refer to any .NET API and may be in any .NET language. 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. Cmdlets can use .NET data access APIs directly or use the PowerShell infrastructure of PowerShell Providers, which make data stores addressable using unique paths. Data stores are exposed using drive letters, and hierarchies within them, addressed as directories. Windows PowerShell ships with providers for the file system, registry, the certificate store, as well as the namespaces for command aliases, variables, and functions. Windows PowerShell also includes various cmdlets for managing various Windows systems, including the file system, or using Windows Management Instrumentation to control Windows components. Other applications can register cmdlets with PowerShell, thus allowing it to manage them, and, if they enclose any datastore (such as databases), they can add specific providers, as well.

In PowerShell V2, a more portable version of Cmdlets called Modules have been added. The PowerShell V2 release notes state:

"Modules allow script developers and administrators to partition and organize their Windows PowerShell code in self-contained, reusable units. Code from a module executes in its own self-contained context and does not affect the state outside of the module. Modules also enable you to define a restricted runspace environment by using a script."

Pipeline

PowerShell implements the concept of a pipeline, which enables the output of one cmdlet to be piped as input to another cmdlet. For example, the output of the Get-Process cmdlet could be piped to the Where-Object to filter any process that has less than 1 MB of paged memory, and then to the Sort-Object cmdlet (e.g., to sort the objects by handle count), and then finally to the Select-Object cmdlet to select just the first 10 (i.e., the 10 processes based on handle count).

As with Unix pipelines, PowerShell pipelines are used to compose complex commands, using the | operator to connect stages. However, the PowerShell pipeline differs from Unix pipelines in that stages execute within the PowerShell runtime rather than as a set of processes coordinated by the operating system, and structured .NET objects, rather than byte streams, are passed from one stage to the next. 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. An object can also encapsulate certain functions that work on the contained data, which become available to the recipient command for use. For the last cmdlet in a pipeline, PowerShell automatically pipes its output object to the Out-Default cmdlet, which transforms the objects into a stream of format objects and then renders those to the screen.

Because all PowerShell objects are .NET objects, they share a .ToString() method, which retrieves the text representation of the data in an object. 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 backwards 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.

Scripting

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, as well as integration with .NET. Variables in PowerShell scripts have names that start with $; they can be assigned any value, including the output of cmdlets. Strings can be enclosed either in single quotes or in double quotes: when using double quotes, variables will be expanded even if they are inside the quotation marks. Enclosing the path to a file in braces preceded by a dollar sign (as in ${C:\foo.txt}) creates a reference to the contents of the file. If it is used as an L-value, anything assigned to it will be written to the file. When used as an R-value, the contents of the file will be read. If an object is assigned, it is serialized before being stored.

Object members can be accessed using . notation, as in C# syntax. 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. PowerShell also provides arrays and associative arrays. 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.

Using the function keyword, PowerShell provides for the creation of functions, the following general form:

function name ($Param1, $Param2)
{
  Instructions
}

The defined function is invoked in either of the following forms:

name value1 value2
name -Param1 value1 -Param2 value2

PowerShell supports named parameters, positional parameters, switch parameters and dynamic parameters.

PowerShell allows any .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, [System.Console]::WriteLine("PowerShell"). Objects are created using the New-Object cmdlet. Calling methods of .NET objects is accomplished by using the regular . notation.

PowerShell scripting language 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.

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). However, the action-or-error is configurable; in case of an error, PowerShell can be configured to silently resume execution, without actually throwing the exception.

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 are used 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 scripting language supports binary prefix notation similar to the scientific notation supported by many programming languages in the C-family.

Hosting

Another use of PowerShell is being embedded in a management application, which uses the PowerShell runtime to implement the management functionality. For this, PowerShell provides a managed hosting API. Via the APIs, the application can instantiate a runspace (one instantiation of the PowerShell runtime), which runs in the application's process and is exposed as a Runspace object. The state of the runspace is encased in a SessionState object. When the runspace is created, the Windows PowerShell runtime initializes the instantiation, including initializing the providers and enumerating the cmdlets, and updates the SessionState object accordingly. The Runspace then must be opened for either synchronous processing or asynchronous processing. After that it can be used to execute commands.

To execute a command, a pipeline (represented by a Pipeline object) must be created and associated with the runspace. The pipeline object is then populated with the cmdlets that make up the pipeline. For sequential operations (as in a PowerShell script), a Pipeline object is created for each statement and nested inside another Pipeline object. When a pipeline is created, Windows PowerShell invokes the pipeline processor, which resolves the cmdlets into their respective assemblies (the command processor) and adds a reference to them to the pipeline, and associates them with InputPipe, Outputpipe and ErrorOutputPipe objects, to represent the connection with the pipeline. The types are verified and parameters bound using reflection. Once the pipeline is set up, the host calls the Invoke() method to run the commands, or its asynchronous equivalent - InvokeAsync(). If the pipeline has the Write-Host cmdlet at the end of the pipeline, it writes the result onto the console screen. If not, the results are handed over to the host, which might either apply further processing or display it itself.

The hosting APIs are used by Microsoft Exchange Server 2007 to provide its management GUI. Each operation exposed in the GUI is mapped to a sequence of PowerShell commands (or pipelines). The host creates the pipeline and executes them. In fact, the interactive PowerShell console itself is a PowerShell host, which interprets the scripts entered at command line and creates the necessary Pipeline objects and invokes them.

Versions

Initially using the code name "Monad", PowerShell was first shown publicly at the Professional Developers Conference in September 2003. All major releases are still supported, and each major release has featured backwards compatibility with preceding versions.

PowerShell 1.0

PowerShell 1.0 was released in November 2006 for Windows XP SP2, Windows Server 2003 and Windows Vista. It is an optional component of Windows Server 2008.

PowerShell 2.0

File:GPowerShell.PNG

Windows PowerShell ISE v2.0, an integrated development environment for PowerShell scripts

PowerShell 2.0 is integrated with Windows 7 and Windows Server 2008 R2 and is released for Windows XP with Service Pack 3, Windows Server 2003 with Service Pack 2, and Windows Vista with Service Pack 1.

PowerShell V2 includes changes to the scripting language and hosting API, in addition to including more than 240 new cmdlets.

New features of PowerShell 2.0 include:

• PowerShell Remoting: Using WS-Management, PowerShell 2.0 allows scripts and cmdlets to be invoked on a remote machine or a large set of remote machines.
• Background Jobs: Also called a PSJob, it allows a command sequence (script) or pipeline to be invoked asynchronously. Jobs can be run on the local machine or on multiple remote machines. An interactive cmdlet in a PSJob blocks the execution of the job until user input is provided.
• Transactions: Enable cmdlet and developers can perform transactional operations. PowerShell 2.0 includes transaction cmdlets for starting, committing, and rolling back a PSTransaction as well as features to manage and direct the transaction to the participating cmdlet and provider operations. The PowerShell Registry provider supports transactions.
• ScriptCmdlets: These are cmdlets written using the PowerShell scripting language. The preferred name for script cmdlets is now Advanced Functions.
• SteppablePipelines: This allows the user to control when the BeginProcessing(), ProcessRecord() and EndProcessing() functions of a cmdlet are called.
• Modules: This allows script developers and administrators to organize and partition PowerShell scripts in self-contained, reusable units. Code from a module executes in its own self-contained context and does not affect the state outside the module. Modules can define a restricted runspace environment by using a script. They have a persistent state as well as public and private members.
• Data Language: A domain-specific subset of the PowerShell scripting language that allows data definitions to be decoupled from the scripts and allows localized string resources to be imported into the script at runtime (Script Internationalization).
• Script Debugging: It allows breakpoints to be set in a PowerShell script or function. Breakpoints can be set on lines, line & columns, commands and read or write access of variables. It includes a set of cmdlets to control the breakpoints via script.
• Eventing: This feature allows listening, forwarding, and acting on management and system events. Eventing allows PowerShell hosts to be notified about state changes to their managed entities. It also enables PowerShell scripts to subscribe to ObjectEvents, PSEvents, and WmiEvents and process them synchronously and asynchronously.
• Windows PowerShell Integrated Scripting Environment (ISE): PowerShell 2.0 includes a GUI-based PowerShell host that provides integrated debugger, syntax highlighting, tab completion and up to 8 PowerShell Unicode-enabled consoles (Runspaces) in a tabbed UI, as well as the ability to run only the selected parts in a script.
• Network File Transfer: Native support for prioritized, throttled, and asynchronous transfer of files between machines using the Background Intelligent Transfer Service (BITS).
• New Cmdlets: Including Out-GridView, which displays tabular data in the WPF GridView object.
• New Operators: -Split, -Join, and Splatting (@) operators.
• Exception Handling with Try-Catch-Finally: Unlike other .NET languages, this allows multiple exception types for a single catch block.
• Nestable Here-Strings: PowerShell Here-Strings have been improved and can now nest.
• Block Comments: PowerShell 2.0 supports block comments using <# and #> as delimiters.
• New APIs: The new APIs range from handing more control over the PowerShell parser and runtime to the host, to creating and managing collection of Runspaces (RunspacePools) as well as the ability to create Restricted Runspaces which only allow a configured subset of PowerShell to be invoked. The new APIs also support participation in a Windows PowerShell managed transaction.

PowerShell 3.0

PowerShell 3.0 is integrated with Windows 8 and with Windows Server 2012. Microsoft has also made PowerShell 3.0 available for Windows 7 with Service Pack 1, for Windows Server 2008 with Service Pack 1, and for Windows Server 2008 R2 with Service Pack 1.

PowerShell 3.0 is part of a larger package, Windows Management Framework 3.0 (WMF3), which also contains the WinRM service to support remoting. Microsoft made several Community Technology Preview releases of WMF3. An early community technology preview 2 (CTP 2) version of Windows Management Framework 3.0 was released on 2 December 2011. Since then, updated versions have been shipped in the Windows 8 and Server 2012 beta and release candidate versions.

New features in PowerShell 3.0 include:

• Scheduled jobs: Jobs can be scheduled to run on a preset time and date.
• Session connectivity: Sessions can be disconnected and reconnected. Remote sessions have become more tolerant of temporary network failures.
• Improved code writing: Code completion (IntelliSense) and snippets are added. PowerShell ISE allows users to use dialog boxes to fill in parameters for PowerShell cmdlets.
• Delegation support: Administrative tasks can be delegated to users who do not have permissions for that type of task, without granting them perpetual additional permissions.
• Help update: Help documentations can be updated via Update-Help command.
• Automatic module detection: Modules are loaded implicitly whenever a command from that module is invoked. Code completion works for unloaded modules as well.
• New commands: Dozens of new modules were added, including functionality to manage disks, volumes, firewalls, network connections and printer management, previously performed via WMI.

PowerShell 4.0

PowerShell 4.0 is integrated with Windows 8.1 and with Windows Server 2012 R2. Microsoft has also made PowerShell 4.0 available for Windows 7 SP1, Windows Server 2008 R2 SP1 and Windows Server 2012.

New features in PowerShell 4.0 include:

• Desired State Configuration: Declarative language extensions and tools that enable the deployment and management of configuration data for systems using the DMTF management standards and WS-Management Protocol.
• New Default Execution Policy: On Windows Servers, the default execution Policy is now RemoteSigned
• Save-Help: Help can now be saved for modules that are installed on remote computers.
• Enhanced debugging: The debugger now supports debugging workflows, remote script execution and preserving debugging sessions across PowerShell session reconnections.
• -PipelineVariable switch: A new ubiquitous parameter to expose the current pipeline object as a variable for programming purposes.
• Network diagnostics to manage physical and Hyper-V's virtualized network switches.
• Where and ForEach method syntax provides an alternate method of filtering and iterating over objects.

PowerShell 5.0

An initial public preview of PowerShell 5.0 was made available with Windows Management Framework 5.0 (WMF5) on April 3, 2014. Key features include OneGet PowerShell cmdlets to support Chocolatey's repository-based package management and extending support for switch management to layer 2 network switches.

On November 18, 2014, Microsoft released the November 2014 Preview of the Windows Management Framework Core 5.0 package. Improvements were made to Desired State Configuration (DSC), OneGet, PowerShellGet, PowerShell class definitions, and debugging for PowerShell background jobs and PowerShell runspaces in remote processes. On August 31, 2015, Microsoft released a further preview of its Windows Management Framework (WMF) 5.0 solution billed as "production ready", and which will be fully supported until 90 days after WMF 5.0 RTM.

PowerShell 5.0 was released to web on December 16, 2015, only to be retracted on December 23, because of an unresolved bug. Once the bug was fixed, PowerShell 5.0 was re-released 70 days later on February 24, 2016.

New features in PowerShell 5.0 include:

• PowerShell class definitions (properties, methods)
• PowerShell .NET Enumerations
• Debugging for PowerShell Runspaces in remote processes
• Debugging for PowerShell Background Jobs
• Desired State Configuration (DSC) Local Configuration Manager (LCM) version 2.0
• DSC partial configurations
• DSC Local Configuration Manager meta-configurations
• Authoring of DSC resources using PowerShell classes

Comparison of cmdlets with similar commands

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.

PowerShell (Cmdlet)	PowerShell (Alias)	CMD.EXE / COMMAND.COM	Unix shell	Description
Get-ChildItem	gci, dir, ls	dir	ls	List all files / directories in the (current) directory
Test-Connection	N/A	ping	ping	Sends ICMP echo requests to specified machine from the current machine, or instructs another machine to do so
Get-Content	gc, type, cat	type	cat	Get the content of a file
Get-Command	gcm	help	type, which, compgen	List available commands
Get-Help	help, man	help	apropos, man	Help on commands
Clear-Host	cls, clear	cls	clear	Clear the screen
Copy-Item	cpi, copy, cp	copy	cp	Copy one or several files / a whole directory tree
Move-Item	mi, move, mv	move	mv	Move a file / a directory to a new location
Remove-Item	ri, del, erase, rmdir, rd, rm	del, erase, rmdir, rd	rm, rmdir	Delete a file / a directory
Rename-Item	rni, ren, mv	ren, rename	mv	Rename a file / a directory
Get-Location	gl, cd, pwd	cd	pwd	Display the current directory/present working directory.
Pop-Location	popd	popd	popd	Change the current directory to the directory most recently pushed onto the stack
Push-Location	pushd	pushd	pushd	Push the current directory onto the stack
Set-Location	sl, cd, chdir	cd, chdir	cd	Change the current directory
Tee-Object	tee	N/A	tee	Pipe input to a file or variable, then pass the input along the pipeline
Write-Output	echo, write	echo	echo	Print strings, variables etc. to standard output
Get-Process	gps, ps	tlist, tasklist	ps	List all currently running processes
Stop-Process	spps, kill	kill, taskkill	kill	Stop a running process
Select-String	sls	find, findstr	grep	Print lines matching a pattern
Set-Variable	sv, set	set	env, export, set, setenv	Set the value of a variable / create a variable
Invoke-WebRequest	iwr, curl, wget	N/A	wget, cURL	Gets content from a web page on the Internet

Notes

File extensions

• PS1 – Windows PowerShell shell script
• PSD1 – Windows PowerShell data file (for Version 2)
• PSM1 – Windows PowerShell module file (for Version 2)
• PS1XML – Windows PowerShell format and type definitions
• CLIXML – Windows PowerShell serialized data
• PSC1 – Windows PowerShell console file
• PSSC – Windows PowerShell Session Configuration file

Application support

Snap-ins and hosts

Application	Version	Cmdlets	Provider	Management GUI
Exchange Server	2007	402	Yes	Yes
Windows Server	2008	Yes	Yes	No
Microsoft SQL Server	2008	Yes	Yes	No
Microsoft SharePoint	2010	Yes	Yes	No
System Center Configuration Manager	2012 R2	400+	Yes	No
System Center Operations Manager	2007	74	Yes	No
System Center Virtual Machine Manager	2007	Yes	Yes	Yes
System Center Data Protection Manager	2007	Yes	No	No
Windows Compute Cluster Server	2007	Yes	Yes	No
Microsoft Transporter Suite for Lotus Domino	08.02.0012	47	No	No
Microsoft PowerTools for Open XML	1.0	33	No	No
IBM WebSphere MQ	6.0.2.2	44	No	No
Quest Management Shell for Active Directory	1.6	95	No	No
Special Operations Software Specops Command	1.0	Yes	No	Yes
VMware vSphere PowerCLI	6.3 R1	455	Yes	Yes
Internet Information Services	7.0	54	Yes	No
Windows 7 Troubleshooting Center	6.1	Yes	No	Yes
Microsoft Deployment Toolkit	2010	Yes	Yes	Yes
NetApp Data ONTAP PowerShell Toolkit	4.1	1848	Yes	Yes
JAMS Scheduler – Job Access & Management System	5.0	52	Yes	Yes
UIAutomation	0.8	432	No	No
Dell Equallogic	3.5	55	No	No
LOGINventory	5.8	Yes	Yes	Yes
SePSX	0.4.1	39	No	No

Alternative implementation

A project named Pash (the name is a pun on the well-known "bash" Unix shell) has been an open source and cross-platform reimplementation of PowerShell via the Mono framework. Pash was created by Igor Moochnick, written in C# and was released under the GNU General Public License. Pash development stalled in 2008, but was restarted in 2012.

See also

• Common Information Model
• Comparison of command shells
• Comparison of programming languages
• Web-Based Enterprise Management
• Windows Script Host

External links

• Windows PowerShell Survival Guide on TechNet Wiki