Unix is pretty amazing for many things.
I mostly love its philosophy of making small composable tools that do one thing and do it well.
/dev/tty is a synonym for the controlling terminal (if any) of the current process.
AT&T Archives: The UNIX Operating System - Awesome lookback on history of UNIX.
cicada - Simple Unix shell written in Rust.
Awesome UNIX - All the UNIX and UNIX-Like: Linux, BSD, macOS, Illumos, 9front, and more.
Relational pipes - Open data format designed for streaming structured data between two processes.
Cron Helper - Cron syntax for us humans.
Cronie - Standard UNIX daemon crond that runs specified programs at scheduled times and related tools.
Unix History Repository - Continuous Unix commit history from 1970 until today.
USENIX - Advanced Computing Systems Association.