journalctl
journalctl is a command-line utility for querying and displaying logs from the systemd journal, which is a centralized logging system on Linux distributions that use systemd. It provides a structured and indexed approach to log management, allowing users to filter, search, and analyze system and application logs efficiently. The tool is integral to troubleshooting, monitoring, and auditing system activities on modern Linux systems.
Developers should learn journalctl when working with Linux systems that use systemd, as it is the primary tool for accessing logs in environments like Ubuntu, Fedora, and CentOS. It is essential for debugging system issues, monitoring service performance, and analyzing security events, offering advanced filtering options such as by time, unit, priority, and custom fields. Use cases include diagnosing service failures, tracking application errors, and performing log analysis for compliance or operational insights.