Linux.com: CLI Magic: It’s About Time

“Setting your computer to the correct time is essential because
so many things depend on it: log files, email servers, cron jobs,
and timed alerts among them. This article explains how to set and
maintain accurate time on your system from the command line
interface.

“When your computer is turned off, the hardware clock–a.k.a.
the CMOS clock–keeps the time. In contrast, when Linux is running
the system time–the time kept by the kernel–is the definitive
time source. System time is more accurate than CMOS time. It’s the
time provided by the date command, and it is measured as the number
of seconds since 00:00:00 January 1, 1970 UTC. The only way to keep
correct UTC time on your computer is to synchronize with an
external time source…”

Complete
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