Linux

Installation date

Source

# Method a
sudo tune2fs -l /dev/sda1 | grep 'Filesystem created:'

# Method b
sudo rpm -qi basesystem | grep Install

Forced reboot

Source

If the usual shutdown/reboot fails:

# Enable SysRq
echo 1 > /proc/sys/kernel/sysrq

# Immediate reboot
echo b > /proc/sysrq-trigger

journalctl

Source

By Unit

journalctl -u <unit>.service [--since today]

By component

journalctl /usr/bin/bash

By priority

journalctl -p <prioritynumber|priority> -b

• 0: emerg
• 1: alert
• 2: crit
• 3: err
• 4: warning
• 5: notice
• 6: info
• 7: debug