PowerShell require minimum version

I have some PowerShell scripts that had a dependency on using at least PowerShell 4.0. I’d added #Require -Version 4.0 to the top of the script, but was surprised the other day when this script ran on a machine with only PowerShell 2.0 and it didn’t complain. Well it did complain about other things (related to trying to run on the older version), but it didn’t throw up an error about the wrong version immediately like I’d expected.

Double-checking the documentation for About_Requires, I realised I’d made a minor (but significant) typo.

#Requires -Version 4.0

Yeah - a missing ‘s’. Without that, it’s just a commented line rather than a directive, so it was having no effect.

As it happens, this script also needs to be run as an Administrator, and whilst browsing same the documentation discovered there’s also a Requires prerequisite for that too!

#Requires -RunAsAdministrator

Trying to run the script non-elevated results in the following error:

.\Script.ps1 : The script 'Script.ps1' cannot be run because it contains a "#requires" statement for running as Administrator. The current PowerShell session is not running as Administrator. Start PowerShell by using the Run as Administrator option, and then try running the script again.
Written on October 18, 2019