I want to learn about Linux and how to use it. Can anybody share with me what they know about Linux and how to use it? Does anybody know where I can find information about Linux and how to use it?
The best way to learn to use Linux is to install a Linux distribution on your computer and just start using it. If you install any of the popular distributions you'll get a graphical/windowing user interface similar to Windows and Mac OS and you shouldn't have too much difficulty figuring out how to use it to do basic things like run programs. I don't think you really need a tutorial or book to tell you how to click on an icon.
That said, there are some things that are done differently in Linux that might confuse you that you should be aware of. Probably the main one, if you're a beginner used to Windows, is that software is managed more centrally on Linux and the
way you install programs is different than the way you do it in Windows.
Another one you won't see immediately but might start to notice is that Linux is much more modular than Windows. For example in Linux, unlike Windows, the GUI (desktop/window system) isn't an integrated part of the operating system but a separate program (actually a collection of programs). This means you can run a lot of different GUIs on top of Linux, from full desktop environments like KDE:
to minimal window managers like twm:
(note the simpler graphics and the absence of any kind of task bar in the second picture). It's also possible to run Linux with no GUI at all.
At some point, if you want to learn more than the basics, you'll want to learn to use the command line. (Windows also has a command line, but it's vestigial compared with Linux and mainly meant for running old DOS programs.) On this, I think
this old article on the Unix "software tools" philosophy and, maybe later, Eric Raymond's book
The Art of Unix Programming (
available free online) make good reading concerning the philosophy and approach to software that Unix (which Linux is a variant of) comes from.
Is Linux fast, free, and secure?
It makes a good operating system. Personally I much prefer using it over Windows for various reasons.
In my experience Linux is more responsive than Windows but how performant it is depends on the computer you are running it on and how you have it set up. See the two different GUI systems above? One of them needs a lot more memory and resources than the other one.
Depends what you mean, since Linux-based operating systems run on everything from supercomputers to smartphones. If you count smartphones and tablets then probably a lot of people are using a Linux-based OS (Android) without realising it.
If you're asking about desktop/PC use, then last I heard only 1-2% of people were using Linux as a desktop OS, although it varies a lot by background/profession. Among physicists, for example, I've seen about as many people using Linux as Mac OS or Windows.
I have heard of Linux Mint and Linux Ubuntu before. Does anybody use and like these two versions of Linux?
These are among the most popular desktop Linux distributions. Both are good choices as a first Linux distribution. Linux Mint is probably the better choice if you want to have common but patented multimedia formats like mp3 working easily. It's also possible to install them on Ubuntu but you'll need to jump through some hoops to do it.