Linux: The system under everything

Linux is a set of honest interfaces, and the shell is how you talk to them.

Everything is a file

Devices, sockets, processes all speak the file API. One interface, many object kinds, that is the design’s whole trick.

Small tools, text streams, pipes between them: the UNIX philosophy. Each tool does one job; combinations are unlimited.

Nine units: boot process, filesystem, shell, processes, users and permissions, system programming, devices, services, and hardening.

Flashcard

The pipe operator

Feed one program’s stdout to another’s stdin. Composition made cheap.

A process killed with SIGKILL (kill -9):