Prof. Powershell

Touch Me, Baby (with Set-ItemProperty, of course)

Here's a way to get beyond the usual looking into file properties and time stamps and start changing them.

• By Jeffery Hicks
• 10/11/2011

Chances are you primarily use Windows PowerShell to look at things like files, services and processes. Of course given the proper credentials you are allowed to touch just about anything. In today's class, I want to show you how to modify file properties such as their attributes and time stamp.

In PowerShell, many things we look at are generically referred to as items. For example, consider Get-ChildItem -- its job is to retrieve all items that are children in the specified or current container. If you know the item name, you can retrieve it with Get-Item:

PS C:\work> get-item foo.txt

   Directory: C:\work

Mode    LastWriteTime      Length   Name
----    -------------      ------   ----
-a---   3/8/2011 7:59 PM   13876    foo.txt

Some items, like files and registry keys, have properties. You can see some of the properties in the output. To see everything you could use the Get-ItemProperty cmdlet:

PS C:\work> get-itemproperty .\foo.txt | select *

To be sure, there are other ways to get the same information but the end result is what matters. Now that I can see some properties, I can change some of them using the Set-ItemProperty cmdlet. See how these things work in pairs? For example, let's say I need to change the file to be read-only and keep the archive flag. I need to specify the item path, the property name and a value:

PS C:\work> set-itemproperty .\foo.txt -Name Attributes -Value "ReadOnly,Archive"

The cmdlet doesn't write to the pipeline unless you use -Passthru, but it made the change:

PS C:\work> get-item .\foo.txt

   Directory: C:\work

Mode   LastWriteTime      Length   Name
----   -------------      ------   ----
-ar--  3/8/2011 7:59 PM   13876    foo.txt

It's not much more work to apply this type of change to multiple files:

PS C:\work> dir *.ps1 | set-itemproperty -Name Attributes -Value "readonly,archive"

I've just set all PowerShell scripts in my Work folder as ReadOnly. This also works on folders:

PS C:\work> set-itemproperty .\secret -name Attributes -Value "Hidden" -PassThru | get-item -force

   Directory: C:\work

Mode   LastWriteTime      Length   Name
----   -------------      ------   ----
d--h-  9/27/2011 9:09 AM           secret

Touching time stamps isn't that much more difficult. I want to leave the creation time alone but update the last write and access times. Here's one approach:

PS C:\work> get-item c:\work\foo.txt | Foreach {
>> $_ | set-itemproperty -Name LastWriteTime -Value "09/10/2011 1:10:00 AM"
>> $_ | set-itemproperty -Name LastAccessTime -Value "09/10/2011 1:10:00 AM" -passthru
>> } | get-item | select Name,Last*
>>

Name              : foo.txt
LastAccessTime    : 9/10/2011 1:10:00 AM
LastAccessTimeUtc : 9/10/2011 5:10:00 AM
LastWriteTime     : 9/10/2011 1:10:00 AM

The UTC times will automatically be updated accordingly.

The next time you feel the need to get all touchy-feely, be sure to look at full help and examples for Set-ItemProperty.