Time concepts, commands, clocks, timers and high resolution sleep and timers are explained. https://www.softprayog.in/tutorials/alarm-sleep-and-high-resolution-timers
0:00 Introduction
2:25 timedatectl command
3:59 Synchronizing system clock
4:57 Hardware clock (RTC)
8:14 Calendar time
12:03 Execution time
17:18 Alarms
18:35 Sleep
21:08 High resolution timers
26:27 POSIX timers
