Input Filter Parameters
A cmdlet can define Filter, Include, and Exclude parameters that filter the set of input objects that the cmdlet affects.
Typically, the set of input objects is specified by an InputObject, Path, or Name parameter. For example, a cmdlet can have a Path parameter that accepts multiple paths by using wildcard characters, and each path points to an input object. Used together, the Filter, Include, and Exclude parameters further qualify the paths the cmdlet works on each time it is invoked.
Include and Exclude Parameters
The Include and Exclude parameters identify the objects that are included or excluded from the set of input objects passed to the cmdlet. Use these parameters when the filter can be expressed in the standard wildcard language. (For more information about wildcard characters, see Supporting Wildcard Characters in Cmdlet Parameters.) The Include parameter includes all the objects whose names match the inclusion filter. The Exclude parameter excludes all the objects whose names match the exclusion filter.
The Filter parameter specifies a filter that is not expressed in the standard wildcard language. For example, Active Directory Service Interfaces (ADSI) or SQL filters might be passed to the cmdlet through its Filter parameter. In the cmdlets provided by Windows PowerShell, these filters are specified by the Windows PowerShell providers that use the cmdlet to access a data store. Each provider typically defines its own filter.
Filtering If No Set of Input Objects Is Specified
If no set of input objects is specified, this typically means to filter against all objects. For more information, see Get-Process.
Other ResourcesWriting a Windows PowerShell Cmdlet