systemd and journalctl cheatsheet
systemd and journalctl: System info and boot analysis
5 common systemd and journalctl tasks.
Show the boot critical path
Show the chain of units that determined boot time.
systemd-analyze critical-chain
Show or set the hostname
Show the hostname and OS details. Set one with hostnamectl set-hostname.
hostnamectl
Show the date, time and timezone
Show time settings and whether the clock is synchronized.
timedatectl