# Reading System Logs

Programs on a Linux computer write down what happens in logs, the files in /var/log and systemd's journal; journalctl -u shows one service's lines, -f watches new ones arrive, and on a Mac log show and the Console app do the same job.

![Cheat sheet for the lesson Reading System Logs: Programs on a Linux computer write down what happens in logs, the files in /var/log and systemd's journal; journalctl -u shows one service's lines, -f watches new ones arrive, and on a Mac log show and the Console app do the same job.](https://fsdtrainingmedia.blob.core.windows.net/public/images/2026/11/2ae4b23de83f4046926f060fdd9716fd.webp)

- Category: Bash
- Level: Journeyman
- Tags: head-and-tail, journalctl, linux, log-file, log-rotation, unix, var-log
- Updated: November 10, 2026

Source: https://www.ask-codey.com/cheat-sheets/bash-system-logs-cheat-sheet