rrdate

A tool for querying the current time from a network server and setting the system time written in Rust. rrdate implements both Simple Network Time Protocol (SNTP) and Time Protocol clients, and provides the rdate command. Unlike traditional rdate implementations, rrdate defaults to using NTP, which is more accurate than Time Protocol.

Installing

cargo install --git https://github.com/guyru/rrdate

Setting time requires running the program as root. Alternatively, you can add the CAP_SYS_TIME capability to the rdate binary:

sudo setcap cap_sys_time+ep ./rdate

This will allow using the program as normal user.

Usage

    rdate [OPTIONS] <HOST>

ARGS:
    <HOST>    Time server (e.g. time.nist.gov)

OPTIONS:
    -a                   Use the adjtime(2) call to gradually skew the local time to the remote time
                         rather than just hopping
    -h, --help           Print help information
    -o, --port <PORT>    Use port 'port' instead of port 37 (RFC 868) or 123 (SNTP, RFC 5905)
    -p, --print          Just print, don't set
        --rfc868         Use RFC 868 time protocol instead of SNTP (RFC 5905)
    -s, --silent         Just set, don't print
    -u                   Use UDP instead of TCP as transport for RFC 868. SNTP will always use UDP
                         protocol
    -v, --verbose        Verbose output
    -V, --version        Print version information

Examples

Query and print the time:

# rdate -p 0.debian.pool.ntp.org
Tue Sep 27 09:50:30 2022

Gradually correct the time:

# rdate -va 0.debian.pool.ntp.org
Precision: 1μs (-21)
Jitter: 52.5μs
Delay: 2ms
Tue Sep 27 09:50:30 2022
adjust local clock by 0.003534 seconds (adjtime)

License

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

Authors

Author: Guy Rutenberg