Rdate
Encyclopedia
On Unix-like
operating systems, rdate is a tool for querying the current time from a network server and, optionally, setting the system time. Rdate uses the Time Protocol
. The Time Protocol is generally considered obsolete and has been replaced by the Network Time Protocol
(NTP).
When used to set the local system time, rdate operates by changing system time immediately to the time and date returned by the server. Abrupt changes of clock settings have been found to cause problems for software relying on timing. This led to the development of the Network Time Protocol
, which gradually changes the system time and does not skip ticks.
Due to the problems described above, rdate is generally used only on systems where NTP is not available, or in specialized circumstances where it is required that system time be set correctly as soon as possible during initial setup, before services which may be vulnerable to abrupt time-changes have started.
Unix-like
A Unix-like operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification....
operating systems, rdate is a tool for querying the current time from a network server and, optionally, setting the system time. Rdate uses the Time Protocol
TIME protocol
The Time Protocol is a network protocol in the Internet Protocol Suite defined in 1983 in RFC 868. Its purpose is to provide a site-independent, machine readable date and time....
. The Time Protocol is generally considered obsolete and has been replaced by the Network Time Protocol
Network Time Protocol
The Network Time Protocol is a protocol and software implementation for synchronizing the clocks of computer systems over packet-switched, variable-latency data networks. Originally designed by David L...
(NTP).
When used to set the local system time, rdate operates by changing system time immediately to the time and date returned by the server. Abrupt changes of clock settings have been found to cause problems for software relying on timing. This led to the development of the Network Time Protocol
Network Time Protocol
The Network Time Protocol is a protocol and software implementation for synchronizing the clocks of computer systems over packet-switched, variable-latency data networks. Originally designed by David L...
, which gradually changes the system time and does not skip ticks.
Due to the problems described above, rdate is generally used only on systems where NTP is not available, or in specialized circumstances where it is required that system time be set correctly as soon as possible during initial setup, before services which may be vulnerable to abrupt time-changes have started.