NAME

     rdate — set the system's date from a remote host

SYNOPSIS

     rdate [-46acnpsuv] [-o port] host

DESCRIPTION

     rdate displays and sets the local date and time from the host name or address given as the
     argument.  The time source may be an RFC 868 TCP protocol server, which is usually
     implemented as a built-in service of inetd(8), or an RFC 2030 protocol SNTP/NTP server.  By
     default, rdate uses the RFC 868 TCP protocol.

     The options are as follows:

     -4      Forces rdate to use IPv4 addresses only.

     -6      Forces rdate to use IPv6 addresses only.

     -a      Use the adjtime(2) call to gradually skew the local time to the remote time rather
             than just hopping.

     -c      Correct leap seconds.  Sometimes required when synchronizing to an NTP server.  When
             synchronizing using the RFC 868 protocol, use this option only if the server does
             not correctly account for leap seconds.  You can determine if you need this
             parameter if you sync against an NTP server (with this parameter) or (recommended)
             check with a local radio controlled watch or phone service.

     -n      Use SNTP (RFC 2030) instead of the RFC 868 time protocol.

     -o port
             Use port port instead of port 37.

     -p      Do not set, just print the remote time.

     -s      Do not print the time.

     -u      Use UDP instead of TCP as transport.

     -v      Verbose output.  Always show the adjustment.

FILES

     /var/log/wtmp  record of date resets and time changes

EXAMPLES

     To get the legal time in Germany, set the /etc/localtime symlink to
     /usr/share/zoneinfo/right/Europe/Berlin and issue the following command:

           # rdate -ncv ptbtime1.ptb.de

     The command of course assumes you have a working internet connection and DNS set up to
     connect to the server at Physikalisch-Technische Bundesanstalt in Braunschweig, Germany.

     To gradually adjust time once an hour after the first "step" adjustment, put the following
     line into root's crontab:

           58  *  *  *  *  rdate -ncav ptbtime1.ptb.de | logger -t NTP

     To to set the time through an ssh tunnel, use something like so:

           ssh -f -L 10037:time.example.com:37 tyr.example.com sleep 10
           rdate -a -o 10037 locahost

SEE ALSO

     date(1), adjtime(2), inetd(8), ntpd(8), timed(8)

AUTHORS

     This manual page was written by Christos Zoulas. It was changed by
     Anibal Monsalve Salazar for the Debian Project.