A bit of terminal trivia for your next coffee break. All five are true, I promise.
1. 'grep' is a sentence, not a word.
Before grep existed, you'd search a file in the ed editor with:
g/re/p
global · regular expression · print. Ken Thompson turned that one command into its own program, and the name stuck.
2. Linux time has an expiry date
$ date -u -d @2147483647
Tue Jan 19 03:14:07 UTC 2038
2147483647 is the biggest number a signed 32-bit integer can hold. Systems that still count seconds since 1970 in 32 bits overflow one second later. 64-bit time counters are good for roughly 292 billion years, so update the old stuff and relax.
3. Daemons are named after a physics demon
sshd, dockerd, containerd: the trailing d is for daemon. In the 1960s, programmers at MIT borrowed the word from Maxwell's demon, a thought experiment about a tiny being that quietly sorts molecules. A background helper nobody sees: a perfect name for a process.
$ ps -e | grep "d$"
4. Tux exists because of a penguin bite
Linus Torvalds likes to tell how a penguin "bit" him at a zoo in Australia. When Linux needed a mascot a few years later, it was going to be a penguin.
5. Docker was revealed in a 5-minute talk
Docker was first shown to the world in a lightning talk at PyCon 2013. Five minutes. Today, a big part of the internet runs in containers.
Bonus: sl
Type sl instead of ls on a machine with the sl package installed and a steam locomotive crosses your terminal. It's a real program, made to punish that exact typo. 🚂
(It also works in DockerLinux, my free browser game for learning Linux and Docker, along with a few other easter eggs.)
Your turn: what's the strangest true fact you know about Linux, Unix or Docker? Best one in the comments might end up in the game. 👇
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