PowerShell Core and Experimental Features

In testing any new feature, one technique for getting users to use (and test) the feature is known as feature flags.  Essentially these are settings (flags) that signal you should gain access to those experimental features. The allows a user to opt-in to testing the new features. Thus is a big application, such as PowerShell, most users just use the published feature set. But if you know how, you can turn on some interesting new features. And of course if you do not like a given experimental feature, you can turn it off.  Let’s look at hot oaccess these features. In this blog post, I am using PowerShell Core 6.2.0-rc.1. If you install different versions, your mileage is going to vary!

Finding Experimental features

Finding experimental features is pretty easy. Hey – this is PowerShell and you should know what to do). Like this:

PS [C:\foo> ]> Get-ExperimentalFeature
Name                        Enabled Source   Description
----                        ------- ------   -----------
PSCommandNotFoundSuggestion   False PSEngine Recommend potential commands based on fuzzy search on a CommandNotFoundException
PSImplicitRemotingBatching    False PSEngine Batch implicit remoting proxy commands to improve performance
PSTempDrive                   False PSEngine Create TEMP: PS Drive mapped to user's temporary directory path
PSUseAbbreviationExpansion    False PSEngine Allow tab completion of cmdlets and functions by abbreviation

So these four experimental feature present on 6.2.0-rc.1 all look pretty cool to me.  The usefulness of these may vary. For me tablcompletion of cmdlet names using abbreviations could interesting. Potentialy really useful so worth looking at even though as I think about it – if the alias is any good, it’s wired into my fingers thus it may be a feature that I never use. Creating the TEMP: folder is something I would take advantage of. The PSCommandNotFoundSuggestion just helps IT Admins to find what they need. And the batching of implicit remoting commands could be very useful if you are, for example, managing Exchange On-Line  using local PowerShell and importing the session.

Enabling Experimental Features

Again – this is PowerShell so: Simples:

PS [C:\foo> ]> Get-ExperimentalFeature | Enable-ExperimentalFeature
WARNING: Enabling and disabling experimental features do not take effect until next start of PowerShell.
WARNING: Enabling and disabling experimental features do not take effect until next start of PowerShell.
WARNING: Enabling and disabling experimental features do not take effect until next start of PowerShell.
WARNING: Enabling and disabling experimental features do not take effect until next start of PowerShell.

So very simple to add in. Due to how these features are implemented you nee to restart Pwsh before you can access the fetures:

Using Experimental Features:

The Command not found suggestion feature is nice. After enabling, PowerShell does a better job of handling typos, like this:

PS [C:\foo> ]> get-chliditem
get-chliditem : The term 'get-chliditem' is not recognized as the name of a cmdlet, function, script file, or operable program.
Check the spelling of the name, or if a path was included, verify that the path is correct and try again.
At line:1 char:1
+ get-chliditem
+ ~~~~~~~~~~~~~
+ CategoryInfo          : ObjectNotFound: (get-chliditem:String) [], CommandNotFoundException
+ FullyQualifiedErrorId : CommandNotFoundException

Suggestion [4,General]: The most similar commands are: Get-ChildItem, Get-ChildItem2.

Nice.  It could be really useful where you have long cmdlet names

Disabling Experimental Features

Needless to say, disabling them is simple too: Use the DisableExperimentalFeature cmdlet to disable the commands.

Summary

Experimental features are PowerShell Core features that may or may not be added to future versions of PowerShell Core. They are easy to enable, consume, and disable as you wish but use at your own risk.