This document describes the use of the NTP Project's ntp-wait program,
that can be used to query a Network Time Protocol (NTP) server and
display the time offset of the system clock relative to the server
clock. Run as root, it can correct the system clock to this offset as
well. It can be run as an interactive command or from a cron job.
This document applies to version 4.2.7p236 of ntp-wait.
The program implements the SNTP protocol as defined by RFC 5905, the NTPv4 IETF specification.
By default, ntp-wait writes the local data and time (i.e., not UTC) to the
standard output in the format:
1996-10-15 20:17:25.123 (+0800) +4.567 +/- 0.089 secs
where YYYY-MM-DD HH:MM:SS.SUBSEC is the local date and time, (+0800) is the local timezone adjustment (so we would add 8 hours and 0 minutes to convert the reported local time to UTC), and the +4.567 +/- 0.089 secs indicates the time offset and error bound of the system clock relative to the server clock.
This section was generated by AutoGen, the aginfo template and the option descriptions for the ntp-wait program. It documents the ntp-wait usage text and option meanings.
This software is released under a specialized copyright license.
This is the automatically generated usage text for ntp-wait:
/deacon/backroom/snaps/ntp-dev/A.snap/scripts/ntp-wait version [unknown] calling Getopt::Std::getopts (version 1.05 [paranoid]),
running under Perl version 5.8.8.
Usage: ntp-wait [-OPTIONS [-MORE_OPTIONS]] [--] [PROGRAM_ARG1 ...]
The following single-character options are accepted:
With arguments: -n -s
Boolean (without arguments): -v
Options may be merged together. -- stops processing of options.
Space is not required between options and their arguments.
[Now continuing due to backward compatibility and excessive paranoia.
See ``perldoc Getopt::Std'' about $Getopt::Std::STANDARD_HELP_VERSION.]
This is the “be verbose” option. By default, ntp-wait is silent. With this option, ntp-wait will provide status information.
The simplest use of this program is as an unprivileged command to check the current time, offset, and error in the local clock. For example:
ntp-wait ntpserver.somewhere
With suitable privilege, it can be run as a command or in a
crom job to reset the local clock from a reliable server, like
the ntpdate and rdate commands.
For example:
ntp-wait -a ntpserver.somewhere