Monday, December 18, 2017

PowerShell oneliner to list all the installed .NET versions on a local computer

In my drawers of PowerShell tools, I have a pretty extensive list of oneliners I have written for specific tasks. Today I want to share the line of code I wrote to check the .NET version installed on a local system. Since there is no direct method to find that information, a lot of people have come up with advanced functions, which is a bit overkill to me. So, given the fact that I like playing with the pipeline, and that I needed a quick and dirty script for this, I decided to see if I could find a way to get this done in just one line of code.

Starting from .NET 1.1 the registry key where the list of installed frameworks is installed is found under:
HKLM\SOFTWARE\Microsoft\NET Framework Setup\NDP
Under this key, you'll see separate keys for each .NET Framework version installed in your system.

Possible paths are:
1.1 HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v1.1.4322
2.0 HKEY_LOCAL_MACHINE\Software\Microsoft\NET Framework Setup\NDP\v2.0.50727
3.0 HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v3.0
3.5 HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v3.5
4.0 HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full
4.5 HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full
4.5.1 HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full
4.5.2 HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full
4.6 HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full
4.6.1 HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full
4.6.2 HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full
As you can see, there are five possible unique paths.

These can be matched with a regular expression:
v1.1.4322$|v2.0.50727$|v3.0$|v3.5$|v4\\Full$
which excludes v4.0 because it is deprecated.

Having PowerShell native access to the registry, we can run the following line on our local computer:
ls 'HKLM:\SOFTWARE\Microsoft\NET Framework Setup\NDP'
just like you'd be browsing your file system.

Now what you have to know is that each .NET framework has a version name and a version number:
  • .NET version name is composed by digits, and comes with the product name i.e. .NET 2.0, .NET 3.5, .NET 4.7.1
  • .NET Version number follows this convention: (Major version).(Minor version).(Revision number).(Build number)

Here's some version numbers I have in my environment:

  • 4.7.02053
  • 4.5.51209
  • 3.5.30729.01
  • 2.1.21022

As you can see version names and version numbers share the first two fields. So, for istance, .NET 4.7.1 has version number 4.7.02556. We can then say that we don't care about the revision or build numbers (third and fourth field). The first two fields are all that I need.

To make a long story short, here's the PowerShell oneliner that I need to run to locally get all the installed .NET releases:
((ls 'HKLM:\SOFTWARE\Microsoft\NET Framework Setup\NDP' -rec|? name -match 'v1.1.4322$|v2.0.50727$|v3.0$|v3.5$|v4\\Full$').name -replace 'HKEY_LOCAL_MACHINE','HKLM:'|%{ Get-ItemProperty $_}).Version
Hope this helps guys. Let me know in the comments if somebody here is able to make my oneliner shorter.

UPDATE: On older PowerShell version use:
((ls 'HKLM:\SOFTWARE\Microsoft\NET Framework Setup\NDP' -rec|? {$_.name -match 'v1.1.4322$|v2.0.50727$|v3.0$|v3.5$|v4\\Full$'} | select -expand name) -replace 'HKEY_LOCAL_MACHINE','HKLM:') -replace 'HKEY_LOCAL_MACHINE','HKLM:'|%{ Get-ItemProperty $_} | select -expand Version

UPDATE: You can also specify this registry path by specifying the registry provider's name, followed by "::". The registry provider's full name is Microsoft.PowerShell.Core\Registry, but this can be shortened to just Registry. So the following syntax is also possible
((ls 'HKLM:\SOFTWARE\Microsoft\NET Framework Setup\NDP' -rec|? name -match 'v1.1.4322$|v2.0.50727$|v3.0$|v3.5$|v4\\Full$').name |%{ Get-ItemProperty "Registry::$($_)"}).Version

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