TOPIC
about_Properties
SHORT DESCRIPTION
Describes how to use object properties in Windows PowerShell.
LONG DESCRIPTION
Windows PowerShell uses structured collections of information called
objects to represent the items in data stores or the state of the computer.
Typically, you work with object that are part of the Microsoft .NET
Framework, but you can also create custom objects in Windows PowerShell.
The association between an item and its object is very close. When you
change an object, you change the item that it represents. For example,
when you get a file in Windows PowerShell, you do not get the actual file.
Instead, you get a FileInfo object that represents the file. When you
change the FileInfo object, the file changes too.
Most objects have properties. Properties are the data that is associated
with an object. This data describes the object. For example, a FileInfo
object has a property called Length that describes the size of the file
that is represented by the object.
Object Properties
To list the properties of an object, use the Get-Member cmdlet. For
example, to get the properties of a FileInfo object, use the Get-ChildItem
cmdlet to get the FileInfo object that represents a file. Then, use a
pipeline operator (|) to send the FileInfo object to Get-Member. The
following command gets the PowerShell.exe file and sends it to Get-Member.
The $Pshome automatic variable contains the path of the Windows PowerShell
installation directory.
get-childitem $pshome\powershell.exe | get-member
The output of the command lists the members of the FileInfo object.
Members include both properties and methods. When you work in
Windows PowerShell, you have access to all the members of the objects.
To get only the properties of an object and not the methods, use the
MemberType parameter of the Get-Member cmdlet with a value of "property",
as shown in the following example.
get-childitem $pshome\powershell.exe | get-member -membertype property
TypeName: System.IO.FileInfo
Name MemberType Definition
---- ---------- ----------
Attributes Property System.IO.FileAttributes Attributes {get;set;}
CreationTime Property System.DateTime CreationTime {get;set;}
CreationTimeUtc Property System.DateTime CreationTimeUtc {get;set;}
Directory Property System.IO.DirectoryInfo Directory {get;}
DirectoryName Property System.String DirectoryName {get;}
Exists Property System.Boolean Exists {get;}
Extension Property System.String Extension {get;}
FullName Property System.String FullName {get;}
IsReadOnly Property System.Boolean IsReadOnly {get;set;}
LastAccessTime Property System.DateTime LastAccessTime {get;set;}
LastAccessTimeUtc Property System.DateTime LastAccessTimeUtc {get;set;}
LastWriteTime Property System.DateTime LastWriteTime {get;set;}
LastWriteTimeUtc Property System.DateTime LastWriteTimeUtc {get;set;}
Length Property System.Int64 Length {get;}
Name Property System.String Name {get;}
After you find the properties, you can use them in your Windows PowerShell
commands.
Property Values
Although every object of a specific type has the same properties, the
values of those properties describe the particular object. For example,
every FileInfo object has a CreationTime property, but the value of that
property differs for each file.
The most common way to get the values of the properties of an object is to
use the dot method. Type a reference to the object, such as a variable
that contains the object, or a command that gets the object. Then, type a
dot (.) followed by the property name.
For example, the following command displays the value of the CreationTime
property of the PowerShell.exe file. The Get-ChildItem command returns a
FileInfo object that represents the PowerShell.exe file. The command is
enclosed in parentheses to make sure that it is executed before any
properties are accessed. The Get-ChildItem command is followed by a dot
and the name of the CreationTime property, as follows:
C:\PS> (Get-ChildItem $pshome\powershell.exe).creationtime
Tuesday, March 18, 2008 12:07:52 AM
You can also save an object in a variable and then get its properties by
using the dot method, as shown in the following example:
C:\PS> $a = Get-ChildItem $pshome\powershell.exe
C:\PS> $a.CreationTime
Tuesday, March 18, 2008 12:07:52 AM
You can also use the Select-Object and Format-List cmdlets to display the
property values of an object. Select-Object and Format-List each have a
Property parameter. You can use the Property parameter to specify one or
more properties and their values. Or, you can use the wildcard
character (*) to represent all the properties.
For example, the following command displays the values of all the
properties of the PowerShell.exe file.
C:\PS> Get-ChildItem $pshome\powershell.exe | Format-List -property *
PSPath : Microsoft.PowerShell.Core\FileSystem::C:\Windows\system32\WindowsPowerShell\v1.0\powershell.exe
PSParentPath : Microsoft.PowerShell.Core\FileSystem::C:\Windows\system32\WindowsPowerShell\v1.0
PSChildName : powershell.exe
PSDrive : C
PSProvider : Microsoft.PowerShell.Core\FileSystem
PSIsContainer : False
VersionInfo : File: C:\Windows\system32\WindowsPowerShell\v1.0\powershell.exe
InternalName: POWERSHELL
OriginalFilename: PowerShell.EXE.MUI
File Version: 6.1.6570.1 (fbl_srv_powershell(nigels).070711-0102)
FileDescription: PowerShell.EXE
Product: Microsoft® Windows® Operating System
ProductVersion: 6.1.6570.1
Debug: False
Patched: False
PreRelease: False
PrivateBuild: True
SpecialBuild: False
Language: English (United States)
BaseName : powershell
Mode : -a---
Name : powershell.exe
Length : 160256
DirectoryName : C:\Windows\system32\WindowsPowerShell\v1.0
Directory : C:\Windows\system32\WindowsPowerShell\v1.0
IsReadOnly : False
Exists : True
FullName : C:\Windows\system32\WindowsPowerShell\v1.0\powershell.exe
Extension : .exe
CreationTime : 3/18/2008 12:07:52 AM
CreationTimeUtc : 3/18/2008 7:07:52 AM
LastAccessTime : 3/19/2008 8:13:58 AM
LastAccessTimeUtc : 3/19/2008 3:13:58 PM
LastWriteTime : 3/18/2008 12:07:52 AM
LastWriteTimeUtc : 3/18/2008 7:07:52 AM
Attributes : Archive
SEE ALSO
about_Objects
Get-Member
Select-Object
Format-List