Short description

Provides essential information about objects in PowerShell.

Long description

Every action you take in PowerShell occurs within the context of objects. As data moves from one command to the next, it moves as one or more identifiable objects. An object, then, is a collection of data that represents an item. An object is made up of three types of data: the objects type, its methods, and its properties.

Types, Methods, and Properties

The object type tells what kind of object it is. For example, an object that represents a file is a FileInfo object.

The object methods are actions that you can perform on the object. For example, FileInfo objects have a CopyTo method that you can use to copy the file.

Object properties store information about the object. For example, FileInfo objects have a LastWriteTime property that stores the date and time that the file was most recently accessed.

When working with objects, you can use their methods and properties in commands to take action and manage data.

You can discover an objects properties and methods using Get-Member or the psobject intrinsic member.

Objects in Pipelines

When commands are combined in a pipeline, they pass information to each other as objects. When the first command runs, it sends one or more objects down the pipeline to the second command. The second command receives the objects from the first command, processes the objects, and then passes new or revised objects to the next command in the pipeline. This continues until all commands in the pipeline run.

The following example demonstrates how objects are passed from one command to the next:

Get-ChildItem C: | where { $_.PsIsContainer -eq $false } | Format-List

The first command Get-ChildItem C: returns a file or directory object for each item in the root directory of the file system. The file and directory objects are passed down the pipeline to the second command.

The second command where { $_.PsIsContainer -eq $false } uses the PsIsContainer property of all file system objects to select only files, which have a value of False ($false) in their PsIsContainer property. Folders, which are containers and, thus, have a value of True ($true) in their PsIsContainer property, are not selected.

The second command passes only the file objects to the third command Format-List, which displays the file objects in a list.

See also