LIOS Logs

/etc is where system-wide configuration lives — almost all of it as plain, editable text files. It's the single place that defines how the machine behaves. A defining Linux strength hides here: configuration is plain text, not a binary registry. That means you can read it, diff i...

Quiz: LIOS / Files and Directories | updated: Jul 30, 2026

Filesystem content splits three ways by how it changes: static (only when you modify it), variable (changes as the system runs), and runtime (created at boot, gone at shutdown). This isn't trivia — it's the principle that explains where a directory should live and on what kind of...

Quiz: LIOS / Files and Directories | updated: Jul 30, 2026

Tilde expansion turns ~ into a home directory path; brace expansion turns {a,b,c} or {1..5} into multiple strings — both are text the shell generates before the command runs. These differ from globbing in a key way: globbing matches files that already exist, but brace expansion i...

Quiz: LIOS / Files and Directories | updated: Jul 30, 2026

Bash lets you edit the command line without arrow keys: Ctrl+A/Ctrl+E jump to line start/end, Alt+B/Alt+F hop word by word, and Ctrl+U/Ctrl+K wipe to the start/end. These come from the Emacs editing mode that bash uses by default, which is why they feel arbitrary until you learn...

Quiz: LIOS / Files and Directories | updated: Jul 30, 2026

Linux's headline strengths are stability, security, open-source transparency, easy automation, broad hardware support, and modularity — the combination is why it took over servers and (as of the mid-2020s) every machine on the Top 500 supercomputer list. These advantages reinforc...

Quiz: LIOS / Linux Introduction | updated: Jul 30, 2026

They're three points on one timeline of the same code: Fedora is the bleeding edge, a Fedora release is frozen and stabilised into CentOS Stream, and CentOS Stream is hardened into a numbered RHEL release that then only gets point updates. * One codebase, three stages of freshne...

Quiz: LIOS / Linux Introduction | updated: Jul 30, 2026

Volatile = journal kept in RAM under /run (wiped on reboot); persistent = written to disk under /var/log/journal (survives reboot). The journal can live in two places, and the difference matters the moment a machine crashes: if storage is volatile, the very logs that would explai...

Quiz: LIOS / Logs, Processes and Services | updated: Jul 30, 2026

Know SIGTERM (15, polite kill), SIGKILL (9, force-kill, uncatchable), SIGHUP (1, reload config), SIGINT (2, Ctrl+C) and SIGSTOP/SIGCONT (pause/resume). * SIGTERM first (graceful, catchable cleanup); escalate to SIGKILL (-9) only if it stays stuck — that forces death with no clea...

Quiz: LIOS / Logs, Processes and Services | updated: Jul 30, 2026

logrotate periodically renames, compresses, and eventually deletes old log files so they don't grow until they fill the disk. Plain-text logs grow forever — a chatty service can fill /var and take the system down. logrotate is the housekeeper that caps this: on a schedule (run by...

Quiz: LIOS / Logs, Processes and Services | updated: Jul 30, 2026

Modern names are "predictable": a type prefix (en/wl/ww) plus the hardware location (e.g. enp0s3 = Ethernet on PCI bus 0, slot 3). The old eth0, eth1, wlan0 names were assigned in detection order, so a name could change between boots if hardware was added — a nightmare for script...

Quiz: LIOS / Network Configuration | updated: Jul 30, 2026