CHRONYC(1) User's Manual CHRONYC(1)NAME
chronyc - command-line interface for chronyd
SYNOPSIS
chronyc [OPTIONS]
DESCRIPTION
chrony is a pair of programs for maintaining the accuracy of computer clocks.
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.
USAGE
A detailed description of all commands supported by chronyc is available via the documentation supplied with the distribution (chrony.txt
and chrony.texi).
OPTIONS
A summary of the options supported by chronyc is included below.
-h hostname
specify hostname
-p port-number
specify port-number
-n display raw IP addresses (don't attempt to look up hostnames)
-4 resolve hostnames only to IPv4 addresses
-6 resolve hostnames only to IPv6 addresses
command
specify command. If no command is given, chronyc will read commands interactively.
VERSION
1.24
BUGS
To report bugs, please visit http://chrony.tuxfamily.org
SEE ALSO chronyd(8), chrony(1)
http://chrony.tuxfamily.org/
AUTHOR
Richard Curnow <rc@rc0.org.uk>
This man-page was written by Jan Schaumann <jschauma@netmeister.org> as part of "The Missing Man Pages Project". Please see
http://www.netmeister.org/misc/m2p2/index.html for details.
The complete chrony documentation is supplied in texinfo format.
chrony December 04, 2009 CHRONYC(1)
Check Out this Related Man Page
CHRONY(1) User's Manual CHRONY(1)NAME
chrony - programs for keeping computer clocks accurate
SYNOPSIS
chronyc [OPTIONS]
chronyd [OPTIONS]
DESCRIPTION
chrony is a pair of programs for keeping computer clocks accurate. chronyd is a background (daemon) program and chronyc is a command-line
interface to it. Time reference sources for chronyd can be RFC1305 NTP servers, human (via keyboard and chronyc), or the computer's real-
time clock at boot time (Linux only). chronyd can determine the rate at which the computer gains or loses time and compensate for it while
no external reference is present. Its use of NTP servers can be switched on and off (through chronyc) to support computers with dial-
up/intermittent access to the Internet, and it can also act as an RFC1305-compatible NTP server.
USAGE
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.
chronyd's main function is to obtain measurements of the true (UTC) time from one of several sources, and correct the system clock accord-
ingly. It also works out the rate at which the system clock gains or loses time and uses this information to keep it accurate between mea-
surements from the reference.
The reference time can be derived from either Network Time Protocol (NTP) servers, reference clocks, or wristwatch-and-keyboard (via
chronyc). The main source of information about the Network Time Protocol is http://www.ntp.org.
It is designed so that it can work on computers which only have intermittent access to reference sources, for example computers which use a
dial-up account to access the Internet or laptops. Of course, it will work well on computers with permanent connections too.
In addition, on Linux it can monitor the system's real time clock performance, so the system can maintain accurate time even across
reboots.
Typical accuracies available between 2 machines are
On an ethernet LAN : 100-200 microseconds, often much better On a V32bis dial-up modem connection : 10's of milliseconds (from one session
to the next)
With a good reference clock the accuracy can reach one microsecond.
chronyd can also operate as an RFC1305-compatible NTP server and peer.
SEE ALSO chronyc(1), chrony(1)
http://chrony.tuxfamily.org/
AUTHOR
Richard Curnow <rc@rc0.org.uk>
This man-page was written by Jan Schaumann <jschauma@netmeister.org> as part of "The Missing Man Pages Project". Please see
http://www.netmeister.org/misc/m2p2/index.html for details.
The complete chrony documentation is supplied in texinfo format.
chrony @VERSION@ @MAN_DATE@ CHRONY(1)