For the PowerShell 10 Year Anniversary, Will Anderson (@GamerLivingWill on Twitter) and I (@MrThomasRayner on Twitter) ran a three-hole code golf competition on code-golf.com, a site developed by fellow MVP Adam Driscoll.

Here is the link to all the background info on the competition: https://github.com/ThmsRynr/PS10YearCodeGolf . Check this page out for links to the individual holes, too.

So, without further delay, let’s announce the winners!

Hole 1

The challenge was to get all the security updates installed on the local computer in the last 30 days and return the results in the form of a [Microsoft.Management.Infrastructure.CimInstance] object (or an array of them).

The winner of this hole is Simon Wåhlin. Here is their 46 character submission.

gcim(gcls *ix*|% *mC*e)|? I*n -gt((date)+-30d)

gcls *ix* gets the CimClass win32_quickfixengineering and % *mC*e gets the CimClassName property. gcim is an alias for Get-CimInstance which, as per the previous section, is getting the win32_quickfixengineering class. The results are piped into the where-object cmdlet where the property matching the pattern I*n (which happens to be InstalledOn) is greater than the current date, minus 30 days.

Hole 2

The challenge was to get the top ten file extensions in c:\windows\system32, only return 10 items and group results by extension.

The winner of this hole is Simon Wåhlin again. Here is their 42 character submission.

(ls C:\*\s*2\*.*|% E*n|group|sort c* -d)[0..9]

ls c:\*\s*2\*.* means Get-ChildItem where the path is c:<em><any directory>\<a directory matching s*2>\<files, not directories> </em>and this pattern only matches the path c:\windows\system32\<files>. This is piped into the foreach-object cmdlet to retrieve the property that matches the pattern E*n,which is the Extension property. The extensions are piped into the sort-object cmdlet, sorted by the property that matches the pattern c*, which is count, and returned in descending order. This is an array, and the items in positions 0-9 are returned.

There were shorter submissions for this hole that didn’t explicitly target c:\windows\system32 and therefore missed the challenge. You could not assume we were already on c: or running as admin, etc. Some solutions included folders in the results which also missed the challenge.

Hole 3

The challenge was to get all the active aliases that are fewer than three characters long and do not resolve to a Get- command. For this hole, even though it wasn’t in the Pester test, you had to assume that non-standard aliases might be on the system. That’s why we specifically mentioned that we didn’t want you to return aliases that resolve to Get-*, and the Pester test checked the ResolvedCommand.Name property of the aliases you returned.

To break some submissions that didn’t check what the aliases resolved to, you could just run New-Alias x Get-ChildItem to create a new alias of ‘x’ that resolves to Get-ChildItem.

The winner of this hole is EdijsPerkums. Here is their 24 character submission.

gal ?,??|? Di* -Notm Get

Get-Alias is passed an array of regex patterns, ?,?? which corresponds to one and two characters. The results are piped into the where-object cmdlet to isolate aliases whose property that matches the pattern Di* (DisplayName) doesn’t match Get.

Congratulations to all the winners! We will be in touch to get you your prizes. We hope you all had fun with this mini-competition. Don’t forget to check out all the terrific material from the PowerShell 10 Year Anniversary on Channel 9!