# Rdate

> Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Rdate
> Markdown URL: https://mediated.wiki/source/Rdate.md
> Source: https://en.wikipedia.org/wiki/Rdate
> Source revision: 1334298460
> License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/)

This article includes a list of references, related reading, or external links, but its sources remain unclear because it lacks inline citations. Please help improve this article by introducing more precise citations. (April 2011) (Learn how and when to remove this message)

Program for querying time on Unix-like systems

On [Unix-like](/source/Unix-like) operating systems, **rdate** is a tool for querying the current time from a network server and, optionally, setting the [system time](/source/System_time). Rdate uses the [Time Protocol](/source/Time_Protocol). The Time Protocol is generally considered obsolete and has been replaced by the [Network Time Protocol](/source/Network_Time_Protocol) (NTP).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](/source/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.

## See also

- [ntpd](/source/Ntpd)

## References

- [rdate(1)](https://linux.die.net/man/1/rdate) – [Linux](/source/Linux) User Commands [Manual](/source/Man_page)

- RFC [868](https://www.rfc-editor.org/rfc/rfc868) – Describing the Time Protocol used by rdate

- [Open-rdate, a project implementing the rdate command](https://sourceforge.net/projects/openrdate/)

v t e Unix command-line utilities and shell builtins File system cat chattr chmod chown chgrp cksum cmp cp dd du df file fuser ln ls mkdir mv pax pwd rm rmdir split tee touch type umask Processes at bg crontab fg kill nice ps time User environment env exit logname mesg talk tput uname who write Text processing awk basename comm csplit cut diff dirname ed ex fold head iconv join m4 more nl paste patch printf read sed sort strings tail tr troff uniq vi wc xargs Shell builtins alias cd echo test unset wait Searching find grep Documentation man Software development ar ctags lex make nm strip yacc Miscellaneous bc cal dc expr lp od sleep true and false Categories Standard Unix programs Unix SUS2008 utilities List

---
Adapted from the Wikipedia article [Rdate](https://en.wikipedia.org/wiki/Rdate) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Rdate?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.