Here are some direct steps to getting PowerCLI 10+ working on Ubuntu Linux.

First thing first, you need to get on a Ubuntu (debian) Machine. Now you need to get Powershell installed:

~$ sudo apt-get install curl
~$ curl  https://packages.microsoft.com/keys/microsoft.asc > MS.key
~$ sudo apt-key add MS.key
~$ curl https://packages.microsoft.com/config/ubuntu/16.04/prod.list | sudo tee /etc/apt/sources.list.d/microsoft.list
~$ sudo apt-get update
~$  sudo apt-get install -y powershell

Awesome! Ok, next you should verify that Powershell is working as expected.

~$ pwsh # <--- THIS IS HOW TO START POWERSHELL
PowerShell v6.0.2
Copyright (c) Microsoft Corporation. All rights reserved.

https://aka.ms/pscore6-docs
Type 'help' to get help.

PS > Get-Date –Format U
Thursday, March 22, 2018 8:57:26 PM
PS > $PSVersionTable

Name                           Value
----                           -----
PSVersion                      6.0.2
PSEdition                      Core
GitCommitId                    v6.0.2
OS                             Linux 4.10.0-28-generic #32~16.04.2-Ubuntu SMP Thu Jul 20 10:19:48 UTC 2017
Platform                       Unix
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1
WSManStackVersion              3.0
PS > exit

Notice the exit, you need to go back to your Ubuntu command prompt to to create a directory. You might be able to do that in the PowerShell prompt, but due to the “non-production” release, it’s best to have this created outside of the shell then recreate it.

~$ mkdir -p ~/.local/share/powershell/Modules

Now go back into Powershell and run the following to install PowerCLI.

~$ pwsh
PowerShell v6.0.2
Copyright (c) Microsoft Corporation. All rights reserved.

https://aka.ms/pscore6-docs
Type 'help' to get help.

PS > Install-Module -Name VMware.PowerCLI  -Scope CurrentUser
Untrusted repository
You are installing the modules from an untrusted repository. If you trust this repository, change its InstallationPolicy
value by running the Set-PSRepository cmdlet. Are you sure you want to install the modules from 'PSGallery'?
[Y] Yes  [A] Yes to All  [N] No  [L] No to All  [S] Suspend  [?] Help (default is "N"): A
PS >

Note: See the -Scope CurrentUser? That is required to make sure that the module gets installed in the local directory we created in the above step.

You should be able to do the following now:

PS > Set-PowerCLIConfiguration -InvalidCertificateAction Ignore
Perform operation?
Performing operation 'Update PowerCLI configuration.'?
[Y] Yes  [A] Yes to All  [N] No  [L] No to All  [S] Suspend  [?] Help (default is "Y"): A

Scope    ProxyPolicy     DefaultVIServerMode InvalidCertificateAction  DisplayDeprecationWarnings WebOperationTimeout
                                                                                                  Seconds
-----    -----------     ------------------- ------------------------  -------------------------- -------------------
Session  UseSystemProxy  Multiple            Ignore                    True                       300
User                                         Ignore
AllUsers

PS > Connect-VIServer -Server SERVERIP -User administrator@vsphere.local -Password YOURPASSWORD
PS > Get-VM