PowerShell Language Keywords

In this tutorial we will see about PowerShell Language Keywords. PowerShell Keywords are used in order to perform a specific action. For this tutorial we will see the list of keywords and the syntax of each one. In related links section you will be able to find a link for each of the keywords in order to check more information about them. I will write a different post for each one of them, in order to see in detail the use of them. Consider this as an introduction to PoowerShell Keywords.

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Keyword List

• Begin – It specifies one part of the body of a function and runs one time before any objects are received from the pipeline.
• Break – It causes a script to exit a loop.
• Catch – It specifies a statement list to run if an error occurs in the accompanying Try statement list.
• Class – It specifies a new class in PowerShell.
• Continue – It causes a script to stop running a loop and to go back to the condition. If the condition is met, the script begins the loop again.
• Data – It defines a section that isolates data from the script logic.
• Define – Reserved for future use
• Do – It is used with the While or Until keyword as a looping construct.
• DynamicParam – It specifies one part of the body of a function. Dynamic parameters are added at run time.
• Else – It is used with the If keyword to specify the default statement list.
• Elseif – It is used with the If and Else keywords to specify additional conditionals. The Else keyword is optional.
• End – It specifies one part of the body of a function and runs one time after all the objects have been received from the pipeline.
• Enum – It is used to declare an enumeration, a distinct type that consists of a set of named labels called the enumerator list.
• Exit – It causes PowerShell to exit a script or a PowerShell instance.
• Filter – It specifies a function in which the statement list runs one time for each input object. It has the same effect as a function that contains only a Process block.
• Finally – It defines a statement list that runs after statements that are associated with Try and Catch.
• For – It defines a loop by using a condition.
• ForEach – It defines a loop by using each member of a collection.
• From – Reserved for future use.
• Function – It creates a named statement list of reusable code.
• Hidden – It hides class members from the default results of the Get-Member cmdlet, and from IntelliSense and tab completion results.
• If – It defines a conditional.
• In – It is used in a ForEach statement to create a loop that uses each member of a collection.
• InlineScript – It runs workflow commands in a shared PowerShell session. InlineScript is valid only in a PowerShell Workflow.
• Param – It defines the parameters in a function.
• Process – It specifies a part of the body of a function.
• Return – It causes PowerShell to leave the current scope and writes the optional expression to the output.
• Static – It specifies the property or method defined is common to all instances of the class in which is defined.
• Switch – The Switch statement is equivalent to a series of If statements, but it is simpler.
• Throw – It throws an object as an error.
• Trap – It defines a statement list to be run if an error is encountered.
• Try – It defines a statement list to be checked for errors while the statements run.
• Until – It is used in a Do statement as a looping construct where the statement list is executed at least one time.
• Using – It allows to indicate which namespaces are used in the session.
• Var – Reserved for future use.
• While  – It is used in a Do statement as a looping construct where the statement list is executed at least one time.

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Function – Param – DynamicParam – Begin – Process – End

Syntax:

function [<scope:>]<name> [([type]$parameter1[,[type]$parameter2])]
{
  param([type]$parameter1 [,[type]$parameter2])
  dynamicparam {<statement list>}
  begin {<statement list>}
  process {<statement list>}
  end {<statement list>}
}

Try – Catch – Finally

Syntax:

try {<statement list>}
catch [[<error type>][',' <error type>]*] {<statement list>}
finally {<statement list>}

Classes – Static

Classes are declared using the following syntax:

class <class-name> [: [<base-class>][,<interface-list]] {
    [[<attribute>] [hidden] [static] <property-definition> ...]
    [<class-name>([<constructor-argument-list>])
      {<constructor-statement-list>} ...]
    [[<attribute>] [hidden] [static] <method-definition> ...]
}

Classes are instantiated using either of the following syntaxes:

[$<variable-name> =] New-Object -TypeName <class-name> [
  [-ArgumentList] <constructor-argument-list>]

[$<variable-name> =] [<class-name>]::new([<constructor-argument-list>])

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Data

Syntax:

DATA [-supportedCommand <cmdlet-name>] {
    <Permitted content>
}

Do-While – Do-Until

Do-While Syntax:

do {<statement list>} while (<condition>)

Do-Until Syntax:

do {<statement list>} until (<condition>)

If – Elseif – Else

Syntax:

if (<test1>)
    {<statement list 1>}
[elseif (<test2>)
    {<statement list 2>}]
[else
    {<statement list 3>}]

Enum

Basic Syntax:

enum <enum-name> {
    <label> [= <int-value>]
    ...
}

Flags Syntax:

[Flags()] enum <enum-name> {
    <label 0> [= 1]
    <label 1> [= 2]
    <label 2> [= 4]
    <label 3> [= 8]
    ...
}

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Filter

Syntax:

filter [<scope:>]<name> {<statement list>}

For

Syntax:

for (<init>; <condition>; <repeat>)
{<statement list>}

ForEach – In

Syntax:

foreach ($<item> in $<collection>){<statement list>}

Return

Syntax:

return [<expression>]

Switch

Syntax:

Switch (<test-value>)
{
    <condition> {<action>}
    <condition> {<action>}
}

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Throw

Syntax:

throw [<expression>]

Trap

Syntax:

trap [[<error type>]] {<statement list>}

Using

Syntax to reference .Net Framework namespaces:

using namespace <.Net-framework-namespace>

Syntax to reference PowerShell modules:

using module <module-name>

I hope the tutorial about PowerShell Language Keywords is helpful.

Please let me know your comments and thoughts.

You feedback is appreciated.

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Related Links

• PowerShell Tutorials
• PowerShell Scripts
• About Language Keywords | Microsoft Docs
• about_Functions | Microsoft Docs
• about_Functions_Advanced | Microsoft Docs
• about_Break | Microsoft Docs
• about_Trap | Microsoft Docs
• about_Try_Catch_Finally | Microsoft Docs
• PowerShell Try Catch Finally – Stephanos Constantinou Blog
• about_Classes | Microsoft Docs
• about_Continue | Microsoft Docs
• about_Trap | Microsoft Docs
• about_Data_Sections | Microsoft Docs
• about_Do | Microsoft Docs
• about_While | Microsoft Docs
• about_Functions_Advanced_Parameters | Microsoft Docs
• about_If | Microsoft Docs
• about_Functions_Advanced_Methods | Microsoft Docs
• about_Enum | Microsoft Docs
• about_For | Microsoft Docs
• about_Foreach | Microsoft Docs
• about_Hidden | Microsoft Docs
• about_Return | Microsoft Docs
• about_Switch | Microsoft Docs
• about_Throw | Microsoft Docs
• about_Using | Microsoft Docs

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Summary

Article Name

PowerShell Language Keywords

Description

PowerShell Language Keywords. In this tutorial you will find information about PowerShell Language Keywords and their use. Stephanos Constantinou Blog

Author

Stephanos

Publisher Name

Stephanos Constantinou Blog

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