Unix

These pages cover the parts of a Linux host an engineer meets while deploying or debugging something, rather than system administration in general. They assume a systemd-based distribution; where a command differs between the RHEL and Debian families, both are given.

Start with the file system if you are looking for where something belongs on disk, networking for interface names and how to read them, and the firewall for why traffic is being dropped. Alternatives covers switching between installed versions of the same tool.

Command-line reference material — the flags themselves — lives in the cheatsheets instead.