journalctl

journalctl -u apache2.service -f

journalctl -S '1h ago'

journalctl --since "2 days ago"

journalctl --since "2018-10-10 18:45" --until "2018-10-10 18:50"

Purging

journalctl --disk-usage

journalctl --vacuum-time="2M"

Values: https://www.man7.org/linux/man-pages/man7/systemd.time.7.html

•   seconds, second, sec, s
•   minutes, minute, min, m
•   hours, hour, hr, h
•   days, day, d
•   weeks, week, w
•   months, month, M (defined as 30.44 days)
•   years, year, y (defined as 365.25 days)