Command syntax

Before you can understand how parameter binding works, you need to understand how to interpret command syntax.The Get-Help and Get-Command cmdlets display syntax diagrams to help you use commands correctly.

Get-Help Get-Command

NAME
    Get-Command

SYNOPSIS
    Gets all commands.

SYNTAX
    Get-Command [[-Name] <System.String[]>] [[-ArgumentList] <System.Object[]>] [-All]
    [-CommandType {Alias | Function | Filter | Cmdlet | ExternalScript | Application |
    Script | Workflow | Configuration | All}] [-FullyQualifiedModule
    <Microsoft.PowerShell.Commands.ModuleSpecification[]>] [-ListImported] [-Module
    <System.String[]>] [-ParameterName <System.String[]>] [-ParameterType
    <System.Management.Automation.PSTypeName[]>] [-ShowCommandInfo] [-Syntax]
    [-TotalCount <System.Int32>] [-UseAbbreviationExpansion] [-UseFuzzyMatching]
    [<CommonParameters>]

    Get-Command [[-ArgumentList] <System.Object[]>] [-All] [-FullyQualifiedModule
    <Microsoft.PowerShell.Commands.ModuleSpecification[]>] [-ListImported] [-Module
    <System.String[]>] [-Noun <System.String[]>] [-ParameterName <System.String[]>]
    [-ParameterType <System.Management.Automation.PSTypeName[]>] [-ShowCommandInfo]
    [-Syntax] [-TotalCount <System.Int32>] [-Verb <System.String[]>] [<CommonParameters>]

Notice the differences between the output from the two commands. Get-Help displays show full type names, while Get-Command shows only short type names. The Get-Help output also shows possible values for some parameters.

Get-Command Get-Command -Syntax

Get-Command [[-ArgumentList] <Object[]>] [-Verb <string[]>] [-Noun <string[]>]
[-Module <string[]>] [-FullyQualifiedModule <ModuleSpecification[]>]
[-TotalCount <int>] [-Syntax] [-ShowCommandInfo] [-All] [-ListImported]
[-ParameterName <string[]>] [-ParameterType <PSTypeName[]>]
[<CommonParameters>]

Get-Command [[-Name] <string[]>] [[-ArgumentList] <Object[]>]
[-Module <string[]>] [-FullyQualifiedModule <ModuleSpecification[]>]
[-CommandType <CommandTypes>] [-TotalCount <int>] [-Syntax] [-ShowCommandInfo]
[-All] [-ListImported] [-ParameterName <string[]>]
[-ParameterType <PSTypeName[]>] [-UseFuzzyMatching]
[-FuzzyMinimumDistance <uint>] [-UseAbbreviationExpansion]
[<CommonParameters>]

Symbols in Syntax Diagrams

The syntax diagram lists the command name, the command parameters, and the parameter values.

The syntax diagrams use the following symbols:

  • A hyphen - indicates a parameter name. In a command, type the hyphen immediately before the parameter name with no intervening spaces, as shown in the syntax diagram.

  • Angle brackets < > indicate placeholder text. You don’t type the angle brackets or the placeholder text in a command. Instead, you replace it with the item that it describes.

    The placeholder inside the angle brackets identifies the .NET type of the value that a parameter takes. For example, to use the Name parameter of Get-Command, replace the <string[]> with one or more strings separated by commas (,).

  • Brackets [] inside of the angle brackets indicate that the parameter can accept one or more values of that type. Enter the values as a comma-separated list.

  • Parameters with no values

    Some parameters don’t accept input, so they don’t have a parameter value. Parameters without values are switch parameters. Switch parameters are used like boolean values. They default to $false. When you use a switch parameter, the value is set to $true.

  • Brackets [ ] around parameters indicate optional items. A parameter and its value can be optional. For example, the CommandType parameter of Get-Command and its value are enclosed in brackets because they’re both optional.

  • Braces {} indicate an enumeration, which is a set of valid values for a parameter.

    The values in the braces are separated by vertical bars |. These bars indicate an exclusive-OR choice, meaning that you can choose only one value from the set of values that are listed inside the braces. For example, the CommandType parameter of Get-Command has a list of possible values in braces.