Is it possible to master several operating systems as a programmer?

Question

Operating Systems

Good afternoon!
As a hobby, I do programming, but from time to time I need to install and configure the Ubuntu server OS, as well as the necessary software to work in it. But I can't do without Windows either.
As with programming languages, in order to master the OS at least superficially, you need to study the basic principles? For example, there is a paging file for Windows and for Linux. There is a constant type in both PHP and Swift.
Thank you!

Answer 1

I am a developer. My home network consists of a couple of freebsd servers, an openbsd router, a linux workstation. I have a macbook because it's a cool machine. There is a weak laptop on windows to read bills, payments and regulatory documents of government agencies. The family has android phones and tablets. This whole economy I have to administer at the very least. Perhaps I did not understand the question?

Answer 2

Is it possible to master several subjects while being a student of a secondary educational institution?
For example, there is a textbook for History and Geometry.

Answer 3

You can :)
And maybe even necessary. At least it won't get worse :)
RSX-11 (only at the user level), SVS/VMS, OS/2, MSDOS, Windows, SCO Unix, FreeBSD, Linux... - something like that ;)