How to capture docker version in powershell cross platform - docker

Question

I'm trying to write a powershell script that gets the version of docker cross platform. This forms the basis of a build script for a larger application which is utilizing docker, so I'd like to verify that a particular version of docker is installed.
Function Exec([Parameter(Mandatory = 1)][scriptblock]$command, $message = '') {
& $command;
if ($global:LastExitCode -ne 0) {
if ($message.Length -eq 0) {
throw "$command exited with code $global:LastExitCode."
}
throw "Exited with code $($global:LastExitCode): $message"
}
}
$version = Exec { docker -v }
This has been working fine on a windows machine, running Powershell 7. It also works on an Azure Ubuntu 20.04 Build Agent. I'm trying to get this to work on a new Ubuntu 20.10 desktop box.
I'm seeing the error write /dev/stdout: permission denied
To diagnose the issue, I removed the Exec function in case that was breaking the pipe in some way, but this still creates the same error:
PS> $version = docker -v
I found this article suggesting it was something to do with needing root https://github.com/moby/moby/issues/31243 but it makes no difference if I use pwsh or sudo pwsh
The following works in bash, but I'd rather use Powershell since most of the developers using this script will be on windows.
#> VERSION=$(docker -v)
#> echo $VERSION
Software used:
Ubuntu 20.10
Docker 19.03.11 (installed with snap install docker)
Powershell 7.1.0 (installed with snap install powershell --classic)
I've tried various ways of invoking bash to get the docker version, but they all error with the same write /dev/stdout: perrmission denied:
$version = sh -c "docker -v"
$version = sh -c "RESULT=$(docker -v);echo `$RESULT"
Interestingly the following works, so I'm guessing it's something to do with powershell and docker
$version = sh -c "RESULT=$(echo 42);echo `$RESULT"
I've tried not capturing the result into a variable and it mostly works:
docker -v # works
sh -c "docker -v" # works
sh -c "RESULT=$(docker -v);echo `$RESULT" # Doesnt work!