There are 2 billion Android phones out there - right now, every one of them is running the Linux operating system under the hood.
Most people don’t know it’s there.
79% of web sites that you visit run Linux (that goes up to 97% if you only count the million most-popular sites). 498 of the 500 fastest computers in the world run Linux.
Most people don’t know it’s there.
But I’m a Linux nut - I use it on my main computer and my laptop every day…so I fondly imagine that I know about these things.
But no. I own 4 TV sets - and the other day, I needed to actually read the instruction book…on the back page, I noticed a page with “Open Source Licenses” listed on it…which is good because if you use OpenSource libraries, you’re required to say so someplace. Guess what? All four of my TVs run Linux! I literally had no idea.
So then I started to look at other instruction books. Turns out my dishwasher and my wife’s car both run Linux…probably other things that I didn’t keep the instructions for - and things made by companies who don’t bother to tell you to, too.
Because small/cheap computers cost less than the price of a MacOS or Windows software license, almost all of IoT (Internet of Things) devices that need an OS at all, will be running Linux…because it’s free and it works very well indeed. I know someone whose front door bell runs Linux.
The Linux kernel contains 20 million lines of code. About 10,000 people have contributed code to it (I’m proud to be one of them) - and it’s FREE.
This is an astounding piece of technology - yet even the people who wrote it are often completely unaware that it’s slipped quietly into some other odd corner of their lives - quietly making things better - rarely taking credit.
Source; Steve, blogger at letsrunwithit.com. 
