A program that gets time from daytime, nist daytime, time, SNTP/NTP, ssh, http or https servers, and optionally updates the system and/or hardware clocks. It can also act as an SNTP server in its own right, or set date and time from the command-line using a number of different date and time formats.
daytime and libUseful are (C) 2010 Colum Paget. They are released under the GPL so you may do anything with them that the GPL allows.
Email: colums.projects@gmail.com Website: www.cjpaget.co.uk
This is free software. It comes with no guarentees and I take no responsiblity if it makes your computer explode or opens a portal to the demon dimensions, though if it does the latter I'd like to be notified.
After unpacking the tar-ball:
tar -zxf daytime-0.1.tar.gz
Do the usual './configure; make; make install'
cd daytime-1.0
./configure
make
make install
daytime -daytime|-time|-nist|-http|-sntp <server> [-s] [-r] [-tz <timezone>]
daytime <url> [-s] [-r] [-tz <timezone>]
daytime -sntp-bcast <broadcast net> [-sntp-version <version>]
daytime -sntpd [-sntp-stratum <stratum>] [-sntp-version <version>]
daytime -S [date or time specifier]
-daytime Get time from daytime (RFC-867, port 13) server
-time Get time from time (RFC-868, port 123) server
-nist Get time from NIST daytime server
-http Get time from a web server
-sntp Get time from a SNTP server. (Not full NTP, only accurate to seconds). If server arg is 'bcast' then wait to recieve sntp broadcast.
-ntp Get time from a SNTP server. (Not full NTP, only accurate to seconds). If server arg is 'bcast' then wait to recieve sntp broadcast.
-sntp-bcast Broadcast SNTP Packets to supplied address. This arg can be used multiple times to bcast to multiple nets on a multihomed host
-sntp-version Version of SNTP in packet. Some devices only accept '1' as the version in sntp broadcasts, when it should be '4'.
-sntp-stratum Stratum of SNTP in packet. This is a measure of how many 'hops' away from an atomic clock an ntp server is. Defaults to '3'.
-sntpd in Daemon mode (implies -d) and provide an SNTP service.
-d Daemon mode. Background and stay running. Needed to recieve broadcast times
-D Daemon mode WITHOUT BACKGROUNDING.
-P Pidfile path for daemon mode.
-t Sleep time. Time between checks when in daemon mode, or between SNTP broadcasts (default 30 secs).
-s Set clock to time we got from server (requires root permissions).
-S Set clock from the command-line (requires root permissions).
-r Set hardware RTC clock
-v verbose output (mainly for SNTP mode)
-l syslog significant events
-tz Timezone of remote host.
-servers List of some servers to try
-? This help
The -nist, -http, -sntp and -ntp optioons do not need a server argument, as they fall back to default servers.
If no server specified, http time from www.google.com will be tried first, then ntp from pool.ntp.org. Servers can be specified as a host/port pair, like 'time.somewhere.com:8080'
The '-S' switch allows setting a date or time from the command-line. This can be expressed in one of the following formats:
HH:MM - time expressed in hours and minutes, date will stay as current.
HH:MM:SS - time expressed in hours, minutes and seconds, date will stay as current.
YYYY/mm/dd - date expressed in year, month, day. Time will stay as current.
dd/mm/YYYY - date expressed in year, month, day. Time will stay as current.
YYYY/mm/dd HH:MM:SS - date and time.
dd/mm/YYYY HH:MM:SS - date and time.
HH:MM:SS YYYY/mm/dd - date and time.
HH:MM:SS dd/mm/YYYY - date and time.
YYYY-mm-ddTHH:MM:SS - date and time.
YYYY/mm/ddTHH:MM:SS - date and time.
Sun Jan 20 15:55:37 GMT 2019 - standard output of the 'date' command
Sun Jan 20 15:55:37 2019 - 'date' style without zone
Jan 20 15:55:37 GMT 2019 - 'date' style without day
Jan 20 15:55:37 2019 - 'date' style without day and zone
any character can be used as a separator in date, but time needs to use ':'
Receiving the time as an SNTP broadcast requires having daytime stay running and wait for the message. To faciliate this a 'daemon mode' has been added. When -d or -D is used, daytime will stay running and do whatever it was told to do periodically. So:
daytime -t 600 -d -sntp-bcast 192.168.1.255 -sntp-bcast 192.168.2.255
Will send sntp broadcasts of the current time to the networks 192.168.1.x and 192.168.2.x. The -t flag can be used to specify a time between broadcasts.
daytime -s -d -sntp bcast
Will persist and wait to recieve sntp broadcasts and set the system time from them. NOTE -t cannot be used in sntp broadcast receive mode
daytime -t 3600 -s -http www.google.com
Will check the time with google via http every hour, and set the system time to it
the -sntpd option will put daytime into SNTP server mode, where it will reply to SNTP requests on port 123. This can be combined with other actions, so for example:
daytime -sntpd -sntp-bcast 192.168.2.255 -daytime time.somewhere.com -t 60
Will run as an SNTP server, updating time using daytime protocol to 'time.somewhere.com' every 60 seconds and sending sntp broadcasts every 60 seconds too
Thanks to Robert Crowley (http://tools.99k.org/) and Andrew Benton for bug reports