Cron jobs and systemd timers

Articles

• flock — preventing a second run — flock holds a file lock while a command runs, so a second copy of the script waits for it or exits at once.
• date — date and time in the shell — The date command: current time, output formats, timestamps for files and logs, date arithmetic.
• journalctl — reading the systemd journal — Command for reading the systemd journal with service, time, and other filters.
• systemctl — managing systemd services — Command for managing systemd units and inspecting their state.
• Cron — the task scheduler — Running tasks on a schedule: crontab syntax, classic cron and modern systemd timers.
• systemd timers — scheduled jobs — A systemd timer is a .timer unit that starts the service of the same name on a schedule; its output goes to the journal.