AWS or Azure or GCP?

Hi AkshayHB-79 

Linux won't be a barrier for you to learn Azure - we have great tools and support for Linux, and many of these Microsoft use ourselves to build some of the platform itself. Most examples give CLI and Powershell sample code. 

Powershell isn't required - there are many ways to get things done through the Azure CLI, APIs, through the Azure portal. BUT... PowerShell is a quite remarkable tool to have in your kitbag, I would highly recommend picking up some familiarity with PowerShell.

Switching clouds... there are many fundamentals, theories, patterns and practices etc, of cloud computing that are true across all cloud environments. There are differences - particularly as you get into the platform-as-a-service offerings, security and compliance approaches... and of course pricing and licensing differences. 

As for AWS and GCP... let's just say that I think it is great to have strong competition to keep the whole industry innovating... but you've made a great choice by starting with Azure !