Windows

Problem

You want to modify or remove a property of a specific registry key.

Solution

To set the value of a registry key, use the SetItemProperty cmdlet:

PS >(GetItemProperty .).MyProgram c:\temp\MyProgram.exe PS >SetItemProperty . MyProgram d:\Lee\tools\MyProgram.exe PS >(GetItemProperty .).MyProgram d:\Lee\tools\MyProgram.exe

To remove the value of a registry key, use the RemoveItemProperty cmdlet:

PS >RemoveItemProperty . MyProgram PS >(GetItemProperty .).MyProgram

Discussion

Problem

You want to view the value of a specific registry key.

Solution

To retrieve the value(s) of a registry key, use the GetItemProperty cmdlet, as shown in Example 181.

Example 181. Retrieving properties of a registry key

Problem

You want to navigate and explore the Windows Registry.

Solution

Use the SetLocation just as you would navigate the filesystem to navigate the registry:

PS >SetLocation HKCU: PS >SetLocation \Software\Microsoft\Windows\CurrentVersion\Run PS >GetLocation

Path

HKCU:\Software\Microsoft\Windows\CurrentVersion\Run

Discussion

As the configuration store for the vast majority of applications, the registry plays a central role in system administration. It is also generally hard to manage.

While commandline tools (such as reg.exe) exist to help you work with the registry, their interfaces are usually inconsistent and confusing. While the Registry Editor graphical user interface is easy to use, it does not support scripted administration.

Discussion

When transporting or archiving files, it is useful to store those files in an archive. ZIP archives are the most common type of archive, so it would be useful to have a script to help manage them.

For many purposes, traditional commandline ZIP archive utilities may fulfill your needs. If they do not support the level of detail or interaction that you need for administrative tasks, a more programmatic alternative is attractive.

Discussion

It is sometimes useful to refer to the same file by two different names or locations. You can’t solve this problem by copying the item, because modifications to one file do not automatically affect the other.

The solution to this is called a hard link, an item of a new name that points to the data of another file. The Windows operating system supports hard links, but only Windows Vista includes a utility that lets you create them.

Discussion

The Explorer shell provides useful information about a file when you click on its Properties dialog. It includes the authoring information, image information, music information, and more.

PowerShell doesn’t expose this information by default, but it is possible to obtain these properties from the Shell.Application COM object. Example 175 does just that—and adds this extended information as properties to the files returned by the GetChildItem cmdlet.

Example 175. AddExtendedFileProperties.ps1

Problem

You want to change the ACL of a file or directory.

Solution

To change the ACL of a file, use the SetAcl cmdlet. This example prevents the Guest account from accessing a file:

$acl = GetAcl example.txt

$arguments = "LEEDESK\Guest","FullControl","Deny"

$accessRule =

NewObject System.Security.AccessControl.FileSystemAccessRule $arguments

$acl.SetAccessRule($accessRule)

$acl | SetAcl example.txt

Discussion

Problem

You want to retrieve the ACL of a file or directory.

Solution

To retrieve the ACL of a file, use the GetAcl cmdlet: PS >GetAcl example.txt

Directory: Microsoft.PowerShell.Core\FileSystem::C:\temp

Path
Owner
Access

example.txt
LEEDESK\Lee
BUILTIN\Administrator...

Discussion

Problem

You want to move a file or directory.

Solution

To move a file or directory, use the MoveItem cmdlet: PS >MoveItem example.txt c:\temp\example2.txt

Discussion

The MoveItem cmdlet moves an item from one location to another. Like the other *Item cmdlets, the MoveItem doesn’t work only against the filesystem. Any providers that support the concept of items automatically support this cmdlet as well.

The MoveItem cmdlet lets you specify multiple files through its Path, Include, Exclude, and Filter parameters.