rdate —
set the system's date from a remote host
rdate displays and sets the local date and time from the
  host name or address given as the argument. It uses the RFC 868 protocol which
  is usually implemented as a built-in service of
  inetd(8).
Available options:
  - -4
- Forces rdateto use IPv4 addresses only.
- -6
- Forces rdateto use IPv6 addresses only.
- -a
- Use the adjtime(2) call to
      gradually skew the local time to the remote time rather than just
    hopping.
- -p
- Do not set, just print the remote time
- -s
- Do not print the time.
  - /var/log/wtmp
- A record of date resets and time changes.