Package chrony

An NTP client/server

https://chrony.tuxfamily.org

A client/server for the Network Time Protocol, this program keeps your
computer's clock accurate. It was specially designed to support
systems with intermittent internet connections, but it also works well
in permanently connected environments. It can use also hardware reference
clocks, system real-time clock or manual input as time references.

General Commands (Section 1)
chronyc
chronyc is a command-line interface program which can be used to monitor chronyd’s performance and to change various operating parameters whilst it is running...
File Formats (Section 5)
chrony.conf
This file configures the chronyd daemon. The compiled-in location is /etc/chrony.conf, but other locations can be specified on the chronyd command line with the...
System Administration (Section 8)
chronyd
chronyd is a daemon for synchronisation of the system clock. It can synchronise the clock with NTP servers, reference clocks (e.g. a GPS receiver), and manual...