neulab/tldr huggingface dataset:
If your report is shorter than two lines, it is almost certainly missing some of these, which makes it hard for us to respond to it.  We're often too polite to close the issue outright, but the missing info makes misinterpretation likely.  As a committer myself, I often get frustrated by these issues, since the only possible way for me to move forward on them is to ask for clarification over and over.
For bug reports, this means that your report should contain the complete output of youtube-dl when called with the -v flag.  The error message you get for (most) bugs even says so, but you would not believe how many of our bug reports do not contain this information.
If your server has multiple IPs or you suspect censorship, adding --call-home may be a good idea to get more diagnostics.  If the error is ERROR: Unable to extract ... and you cannot reproduce it from multiple countries, add --dump-pages (warning: this will yield a rather large output, redirect it to the file log.txt by adding >log.txt 2>&1 to your command-line) or upload the .dump files you get when you add --write-pages somewhere (https://gist.github.com/).
Site support requests must contain an example URL.  An example URL is a URL you might want to download, like https://www.youtube.com/watch?v=BaW_jenozKc.  There should be an obvious video present.  Except under very special circumstances, the main page of a video service (e.g.  https://www.youtube.com/) is not an example URL.
Are you using the latest version? Before reporting any issue, type youtube-dl -U.  This should report that you're up-to-date.  About 20% of the reports we receive are already fixed, but people are using outdated versions.  This goes for feature requests as well.
Is the issue already documented? Make sure that someone has not already opened the issue you're trying to open.  Search at the top of the window or browse the GitHub Issues (https://github.com/ytdl-org/youtube-dl/search?type=Issues) of this repository.  If there is an issue, feel free to write something along the lines of "This affects me as well, with version 2015.01.01.  Here is some more information on the issue: ...".  While some issues may be old, a new post into them often spurs rapid activity.
Why are existing options not enough? Before requesting a new feature, please have a quick peek at the list of supported options (https://github.com/ytdl-org/youtube- dl/blob/master/README.md#options).  Many feature requests are for features that actually exist already!  Please, absolutely do show off your work in the issue report and detail how the existing similar options do not solve your problem.
Is there enough context in your bug report? People want to solve problems, and often think they do us a favor by breaking down their larger problems (e.g.  wanting to skip already downloaded files) to a specific request (e.g.  requesting us to look whether the file exists before downloading the info page).  However, what often happens is that they break down the problem into two steps: One simple, and one impossible (or extremely complicated one).
We are then presented with a very complicated request when the original problem could be solved far easier, e.g.  by recording the downloaded video IDs in a separate file.  To avoid this, you must include the greater context where it is non-obvious.  In particular, every feature request that does not consist of adding support for a new site should contain a use case scenario that explains in what situation the missing feature would be useful.
Does the issue involve one problem, and one problem only? Some of our users seem to think there is a limit of issues they can or should open.  There is no limit of issues they can or should open.  While it may seem appealing to be able to dump all your issues into one ticket, that means that someone who solves one of your issues cannot mark the issue as closed.  Typically, reporting a bunch of issues leads to the ticket lingering since nobody wants to attack that behemoth, until someone mercifully splits the issue into multiple ones.
In particular, every site support request issue should only pertain to services at one site (generally under a common domain, but always using the same backend technology).  Do not request support for vimeo user videos, White house podcasts, and Google Plus pages in the same issue. Also, make sure that you don't post bug reports alongside feature requests.  As a rule of thumb, a feature request does not include outputs of youtube-dl that are not immediately related to the feature at hand. Do not post reports of a network error alongside the request for a new video service.
Is anyone going to need the feature? Only post features that you (or an incapacitated friend you can personally talk to) require.  Do not post features because they seem like a good idea.  If they are really useful, they will be requested by someone who requires them.
Is your question about youtube-dl? It may sound strange, but some bug reports we receive are completely unrelated to youtube-dl and relate to a different, or even the reporter's own, application.  Please make sure that you are actually using youtube-dl.  If you are using a UI for youtube-dl, report the bug to the maintainer of the actual application providing the UI.  On the other hand, if your UI for youtube-dl fails in some way you believe is related to youtube-dl, by all means, go ahead and report the bug.
youtube-dl is released into the public domain by the copyright holders.
This README file was originally written by Daniel Bolton (https://github.com/dbbolton) and is likewise released into the public domain.
CHRONYC(1)                         User manual                        CHRONYC(1)
chronyc - command-line interface for chrony daemon
chronyc [OPTION]... [COMMAND]...
chronyc is a command-line interface program which can be used to monitor chronyd’s performance and to change various operating parameters whilst it is running.
If no commands are specified on the command line, chronyc will expect input from the user. The prompt chronyc> will be displayed when it is being run from a terminal. If chronyc’s input or output are redirected from or to a file, the prompt will not be shown.
There are two ways chronyc can access chronyd. One is the Internet Protocol (IPv4 or IPv6) and the other is a Unix domain socket, which is accessible locally by the root or chrony user. By default, chronyc first tries to connect to the Unix domain socket. The compiled-in default path is /var/run/chrony/chronyd.sock. If that fails (e.g. because chronyc is running under a non-root user), it will try to connect to 127.0.0.1 and then ::1.
Only the following monitoring commands, which do not affect the behaviour of chronyd, are allowed from the network: activity, manual list, rtcdata, smoothing, sourcename, sources, sourcestats, tracking, waitsync. The set of hosts from which chronyd will accept these commands can be configured with the cmdallow directive in the chronyd’s configuration file or the cmdallow command in chronyc. By default, the commands are accepted only from localhost (127.0.0.1 or ::1).
All other commands are allowed only through the Unix domain socket. When sent over the network, chronyd will respond with a ‘Not authorised’ error, even if it is from localhost.
Having full access to chronyd via chronyc is more or less equivalent to being able to modify the chronyd’s configuration file and restart it.
-4 With this option hostnames will be resolved only to IPv4 addresses.
-6 With this option hostnames will be resolved only to IPv6 addresses.
-n This option disables resolving of IP addresses to hostnames, e.g. to avoid slow DNS lookups. Long addresses will not be truncated to fit into the column.
-N This option enables printing of original hostnames or IP addresses of NTP sources that were specified in the configuration file, or chronyc commands. Without the -n and -N option, the printed hostnames are obtained from reverse DNS lookups and can be different from the specified hostnames.
-c This option enables printing of reports in a comma-separated values (CSV) format. Reverse DNS lookups will be disabled, time will be printed as number of seconds since the epoch, and values in seconds will not be converted to other units.
-d This option enables printing of debugging messages if chronyc was compiled with debugging support.
-m Normally, all arguments on the command line are interpreted as one command. With this option multiple commands can be specified. Each argument will be interpreted as a whole command.
-h host This option allows the user to specify which host (or comma-separated list of addresses) running the chronyd program is to be contacted. This allows for remote monitoring, without having to connect over SSH to the other host first.
The default is to contact chronyd running on the same host where chronyc is being run.
-p port This option allows the user to specify the UDP port number which the target chronyd is using for its monitoring connections. This defaults to 323; there would rarely be a need to change this.
-f file This option is ignored and is provided only for compatibility.
-a This option is ignored and is provided only for compatibility.
-v, --version With this option chronyc displays its version number on the terminal and exits.
--help With this option chronyc displays a help message on the terminal and exits.
This section describes each of the commands available within the chronyc program.
System clock tracking The tracking command displays parameters about the system’s clock performance. An example of the output is shown below.
Reference ID    : CB00710F (foo.example.net) Stratum         : 3 Ref time (UTC)  : Fri Jan 27 09:49:17 2017 System time     : 0.000006523 seconds slow of NTP time Last offset     : -0.000006747 seconds RMS offset      : 0.000035822 seconds Frequency       : 3.225 ppm slow Residual freq   : -0.000 ppm Skew            : 0.129 ppm Root delay      : 0.013639022 seconds Root dispersion : 0.001100737 seconds Update interval : 64.2 seconds Leap status     : Normal
The fields are explained as follows:
Reference ID This is the reference ID and name (or IP address) of the server to which the computer is currently synchronised. For IPv4 addresses, the reference ID is equal to the address and for IPv6 addresses it is the first 32 bits of the MD5 sum of the address.
If the reference ID is 7F7F0101 and there is no name or IP address, it means the computer is not synchronised to any external source and that you have the local mode operating (via the local command in chronyc, or the local directive in the configuration file).
The reference ID is printed as a hexadecimal number. Note that in older versions it used to be printed in quad-dotted notation and could be confused with an IPv4 address.
Stratum The stratum indicates how many hops away from a computer with an attached reference clock we are. Such a computer is a stratum-1 computer, so the computer in the example is two hops away (i.e. foo.example.net is a stratum-2 and is synchronised from a stratum-1).
Ref time This is the time (UTC) at which the last measurement from the reference source was processed.
System time In normal operation, chronyd by default never steps the system clock, because any jump in the time can have adverse consequences for certain application programs. Instead, any error in the system clock is corrected by slightly speeding up or slowing down the system clock until the error has been removed, and then returning to the system clock’s normal speed. A consequence of this is that there will be a period when the system clock (as read by other programs) will be different from chronyd’s estimate of the current true time (which it reports to NTP clients when it is operating as a server). The value reported on this line is the difference due to this effect.
Last offset This is the estimated local offset on the last clock update. A positive value indicates the local time (as previously estimated true time) was ahead of the time sources.
RMS offset This is a long-term average of the offset value.
Frequency The ‘frequency’ is the rate by which the system’s clock would be wrong if chronyd was not correcting it. It is expressed in ppm (parts per million). For example, a value of 1 ppm would mean that when the system’s clock thinks it has advanced 1 second, it has actually advanced by 1.000001 seconds relative to true time.
Residual freq This shows the ‘residual frequency’ for the currently selected reference source. This reflects any difference between what the measurements from the reference source indicate the frequency should be and the frequency currently being used.
The reason this is not always zero is that a smoothing procedure is applied to the frequency. Each time a measurement from the reference source is obtained and a new residual frequency computed, the estimated accuracy of this residual is compared with the estimated accuracy (see ‘skew’ next) of the existing frequency value. A weighted average is computed for the new frequency, with weights depending on these accuracies. If the measurements from the reference source follow a consistent trend, the residual will be driven to zero over time.
Skew This is the estimated error bound on the frequency.
Root delay This is the total of the network path delays to the stratum-1 computer from which the computer is ultimately synchronised.
Root dispersion This is the total dispersion accumulated through all the computers back to the stratum-1 computer from which the computer is ultimately synchronised. Dispersion is due to system clock resolution, statistical measurement variations, etc.
An absolute bound on the computer’s clock accuracy (assuming the stratum-1 computer is correct) is given by:
clock_error <= |system_time_offset| + root_dispersion + (0.5 * root_delay)
Update interval This is the interval between the last two clock updates.
Leap status This is the leap status, which can be Normal, Insert second, Delete second or Not synchronised.
makestep, makestep threshold limit Normally chronyd will cause the system to gradually correct any time offset, by slowing down or speeding up the clock as required. In certain situations, the system clock might be so far adrift that this slewing process would take a very long time to correct the system clock.
The makestep command can be used in this situation. There are two forms of the command. The first form has no parameters. It tells chronyd to cancel any remaining correction that was being slewed and jump the system clock by the equivalent amount, making it correct immediately.
The second form configures the automatic stepping, similarly to the makestep directive. It has two parameters, stepping threshold (in seconds) and number of future clock updates for which the threshold will be active. This can be used with the burst command to quickly make a new measurement and correct the clock by stepping if needed, without waiting for chronyd to complete the measurement and update the clock.
makestep 0.1 1 burst 1/2
BE WARNED: Certain software will be seriously affected by such jumps in the system time. (That is the reason why chronyd uses slewing normally.)
maxupdateskew skew-in-ppm This command has the same effect as the maxupdateskew directive in the configuration file.
waitsync [max-tries [max-correction [max-skew [interval]]]] The waitsync command waits for chronyd to synchronise.
Up to four optional arguments can be specified. The first is the maximum number of tries before giving up and returning a non-zero error code. When 0 is specified, or there are no arguments, the number of tries will not be limited.
The second and third arguments are the maximum allowed remaining correction of the system clock and the maximum allowed skew (in ppm) as reported by the tracking command in the System time and Skew fields. If not specified or zero, the value will not be checked.
The fourth argument is the interval specified in seconds in which the check is repeated. The interval is 10 seconds by default.
waitsync 60 0.01
which will wait up to about 10 minutes (60 times 10 seconds) for chronyd to synchronise to a source and the remaining correction to be less than 10 milliseconds.
Time sources sources [-a] [-v] This command displays information about the current time sources that chronyd is accessing.
If the -a option is specified, all sources are displayed, including those that do not have a known address yet. Such sources have an identifier in the format ID#XXXXXXXXXX, which can be used in other commands expecting a source address.
The -v option enables a verbose output. In this case, extra caption lines are shown as a reminder of the meanings of the columns.
MS Name/IP address         Stratum Poll Reach LastRx Last sample =============================================================================== #* GPS0                          0   4   377    11   -479ns[ -621ns] +/-  134ns ^? foo.example.net               2   6   377    23   -923us[ -924us] +/-   43ms ^+ bar.example.net               1   6   377    21  -2629us[-2619us] +/-   86ms
The columns are as follows:
M This indicates the mode of the source. ^ means a server, = means a peer and # indicates a locally connected reference clock.
S This column indicates the selection state of the source.
•   * indicates the best source which is currently selected for synchronisation.
•   + indicates other sources selected for synchronisation, which are combined with the best source.
•   - indicates a source which is considered to be selectable for synchronisation, but not currently selected.
•   x indicates a source which chronyd thinks is a falseticker (i.e. its time is inconsistent with a majority of other sources, or sources specified with the trust option).
•   ~ indicates a source whose time appears to have too much variability.
•   ? indicates a source which is not considered to be selectable for synchronisation for other reasons (e.g. unreachable, not synchronised, or does not have enough measurements).
The selectdata command can be used to get more details about the selection state.
Name/IP address This shows the name or the IP address of the source, or reference ID for reference clocks.
Stratum This shows the stratum of the source, as reported in its most recently received sample. Stratum 1 indicates a computer with a locally attached reference clock. A computer that is synchronised to a stratum 1 computer is at stratum 2. A computer that is synchronised to a stratum 2 computer is at stratum 3, and so on.
Poll This shows the rate at which the source is being polled, as a base-2 logarithm of the interval in seconds. Thus, a value of 6 would indicate that a measurement is being made every 64 seconds. chronyd automatically varies the polling rate in response to prevailing conditions.
Reach This shows the source’s reachability register printed as an octal number. The register has 8 bits and is updated on every received or missed packet from the source. A value of 377 indicates that a valid reply was received for all from the last eight transmissions.
LastRx This column shows how long ago the last good sample (which is shown in the next column) was received from the source. Measurements that failed some tests are ignored. This is normally in seconds. The letters m, h, d or y indicate minutes, hours, days, or years.
Last sample This column shows the offset between the local clock and the source at the last measurement. The number in the square brackets shows the actual measured offset. This can be suffixed by ns (indicating nanoseconds), us (indicating microseconds), ms (indicating milliseconds), or s (indicating seconds). The number to the left of the square brackets shows the original measurement, adjusted to allow for any slews applied to the local clock since. The number following the +/- indicator shows the margin of error in the measurement. Positive offsets indicate that the local clock is ahead of the source.
sourcestats [-a] [-v] The sourcestats command displays information about the drift rate and offset estimation process for each of the sources currently being examined by chronyd.
An example report is:
Name/IP Address            NP  NR  Span  Frequency  Freq Skew  Offset  Std Dev =============================================================================== foo.example.net            11   5   46m     -0.001      0.045      1us    25us
Name/IP Address This is the name or IP address of the NTP server (or peer) or reference ID of the reference clock to which the rest of the line relates.
NP This is the number of sample points currently being retained for the server. The drift rate and current offset are estimated by performing a linear regression through these points.
NR This is the number of runs of residuals having the same sign following the last regression. If this number starts to become too small relative to the number of samples, it indicates that a straight line is no longer a good fit to the data. If the number of runs is too low, chronyd discards older samples and re-runs the regression until the number of runs becomes acceptable.
Span This is the interval between the oldest and newest samples. If no unit is shown the value is in seconds. In the example, the interval is 46 minutes.
Frequency This is the estimated residual frequency for the server, in parts per million. In this case, the computer’s clock is estimated to be running 1 part in 10^9 slow relative to the server.
Freq Skew This is the estimated error bounds on Freq (again in parts per million).
Offset This is the estimated offset of the source.
Std Dev This is the estimated sample standard deviation.
selectdata [-a] [-v] The selectdata command displays information specific to the selection of time sources. If the -a option is specified, all sources are displayed, including those that do not have a known address yet. With the -v option, extra caption lines are shown as a reminder of the meanings of the columns.
An example of the output is shown below.
S Name/IP Address        Auth COpts EOpts Last Score     Interval  Leap ======================================================================= D foo.example.net           Y ----- --TR-    4   1.0   -61ms   +62ms  N * bar.example.net           N ----- -----    0   1.0 -6846us +7305us  N + baz.example.net           N ----- -----   10   1.0 -7381us +7355us  N
S This column indicates the state of the source after the last source selection. It is similar to the state reported by the sources command, but more states are reported.
The following states indicate the source is not considered selectable for synchronisation:
•   N - has the noselect option.
•   M - does not have enough measurements.
•   d - has a root distance larger than the maximum distance (configured by the maxdistance directive).
•   ~ - has a jitter larger than the maximum jitter (configured by the maxjitter directive).
•   w - waits for other sources to get out of the M state.
•   S - has older measurements than other sources.
•   O - has a stratum equal or larger than the orphan stratum (configured by the local directive).
•   T - does not fully agree with sources that have the trust option.
•   x - does not agree with other sources (falseticker).
The following states indicate the source is considered selectable, but it is not currently used for synchronisation:
•   W - waits for other sources to be selectable (required by the minsources directive, or the require option of another source).
•   P - another selectable source is preferred due to the prefer option.
•   U - waits for a new measurement (after selecting a different best source).
•   D - has, or recently had, a root distance which is too large to be combined with other sources (configured by the combinelimit directive).
The following states indicate the source is used for synchronisation of the local clock:
•   + - combined with the best source.
•   * - selected as the best source to update the reference data (e.g. root delay, root dispersion).
Name/IP address This column shows the name or IP address of the source if it is an NTP server, or the reference ID if it is a reference clock.
Auth This column indicites whether an authentication mechanism is enabled for the source. Y means yes and N means no.
COpts This column displays the configured selection options of the source.
•   N indicates the noselect option.
•   P indicates the prefer option.
•   T indicates the trust option.
•   R indicates the require option.
EOpts This column displays the current effective selection options of the source, which can be different from the configured options due to the authentication selection mode (configured by the authselmode directive). The symbols are the same as in the COpts column.
Last This column displays how long ago was the last measurement of the source made when the selection was performed.
Score This column displays the current score against the source in the * state. The scoring system avoids frequent reselection when multiple sources have a similar root distance. A value larger than 1 indicates this source was better than the * source in recent selections. If the score reaches 10, the best source will be reselected and the scores will be reset to 1.
Interval This column displays the lower and upper endpoint of the interval which was expected to contain the true offset of the local clock considering the root distance at the time of the selection.
Leap This column displays the current leap status of the source.
•   N indicates the normal status (no leap second).
•   + indicates that a leap second will be inserted at the end of the month.
•   - indicates that a leap second will be deleted at the end of the month.
•   ? indicates the unknown status (i.e. no valid measurement was made).
reselect To avoid excessive switching between sources, chronyd can stay synchronised to a source even when it is not currently the best one among the available sources.
The reselect command can be used to force chronyd to reselect the best synchronisation source.
reselectdist distance The reselectdist command sets the reselection distance. It is equivalent to the reselectdist directive in the configuration file.
NTP sources activity This command reports the number of servers and peers that are online and offline. If the auto_offline option is used in specifying some of the servers or peers, the activity command can be useful for detecting when all of them have entered the offline state after the network link has been disconnected.
The report shows the number of servers and peers in 5 states:
online the server or peer is currently online (i.e. assumed by chronyd to be reachable)
offline the server or peer is currently offline (i.e. assumed by chronyd to be unreachable, and no measurements from it will be attempted.)
burst_online a burst command has been initiated for the server or peer and is being performed; after the burst is complete, the server or peer will be returned to the online state.
burst_offline a burst command has been initiated for the server or peer and is being performed; after the burst is complete, the server or peer will be returned to the offline state.
unresolved the name of the server or peer was not resolved to an address yet; this source is not visible in the sources and sourcestats reports.
authdata [-a] The authdata command displays information specific to authentication of NTP sources. If the -a option is specified, all sources are displayed, including those that do not have a known address yet. An example of the output is shown below.
Name/IP address             Mode KeyID Type KLen Last Atmp  NAK Cook CLen ========================================================================= foo.example.net              NTS     1   15  256 135m    0    0    8  100 bar.example.net               SK    30   13  128    -    0    0    0    0 baz.example.net                -     0    0    0    -    0    0    0    0
Name/IP address This column shows the name or the IP address of the source.
Mode This column shows which mechanism authenticates NTP packets received from the source. NTS means Network Time Security, SK means a symmetric key, and - means authentication is disabled.
KeyID This column shows an identifier of the key used for authentication. With a symmetric key, it is the ID from the key file. With NTS, it is a number starting at zero and incremented by one with each successful key establishment using the NTS-KE protocol, i.e. it shows how many times the key establishment was performed with this source.
Type This columns shows an identifier of the algorithm used for authentication. With a symmetric key, it is the hash function or cipher specified in the key file. With NTS, it is an authenticated encryption with associated data (AEAD) algorithm, which is negotiated in the NTS-KE protocol. The following values can be reported:
•   1: MD5
•   2: SHA1
•   3: SHA256
•   4: SHA384
•   5: SHA512
•   6: SHA3-224
•   7: SHA3-256
•   8: SHA3-384
•   9: SHA3-512
•   10: TIGER
•   11: WHIRLPOOL
•   13: AES128
•   14: AES256
•   15: AEAD-AES-SIV-CMAC-256
KLen This column shows the length of the key in bits.
Last This column shows how long ago the last successful key establishment was performed. It is in seconds, or letters m, h, d or y indicate minutes, hours, days, or years.
Atmp This column shows the number of attempts to perform the key establishment since the last successful key establishment. A number larger than 1 indicates a problem with the network or server.
NAK This column shows whether an NTS NAK was received since the last request. A NAK indicates that authentication failed on the server side due to chronyd using a cookie which is no longer valid and that it needs to perform the key establishment again in order to get new cookies.
Cook This column shows the number of NTS cookies that chronyd currently has. If the key establishment was successful, a number smaller than 8 indicates a problem with the network or server.
CLen This column shows the length in bytes of the NTS cookie which will be used in the next request.
ntpdata [address] The ntpdata command displays the last valid measurement and other NTP-specific information about the specified NTP source, or all NTP sources (with a known address) if no address was specified. An example of the output is shown below.
Remote address  : 203.0.113.15 (CB00710F) Remote port     : 123 Local address   : 203.0.113.74 (CB00714A) Leap status     : Normal Version         : 4 Mode            : Server Stratum         : 1 Poll interval   : 10 (1024 seconds) Precision       : -24 (0.000000060 seconds) Root delay      : 0.000015 seconds Root dispersion : 0.000015 seconds Reference ID    : 47505300 (GPS) Reference time  : Fri Nov 25 15:22:12 2016 Offset          : -0.000060878 seconds Peer delay      : 0.000175634 seconds Peer dispersion : 0.000000681 seconds Response time   : 0.000053050 seconds Jitter asymmetry: +0.00 NTP tests       : 111 111 1111 Interleaved     : No Authenticated   : No TX timestamping : Kernel RX timestamping : Kernel Total TX        : 24 Total RX        : 24 Total valid RX  : 24
Remote address The IP address of the NTP server or peer, and the corresponding reference ID.
Remote port The UDP port number to which the request was sent. The standard NTP port is 123.
Local address The local IP address which received the response, and the corresponding reference ID.
Leap status, Version, Mode, Stratum, Poll interval, Precision, Root delay, Root dispersion, Reference ID, Reference time The NTP values from the last valid response.
Offset, Peer delay, Peer dispersion The measured values.
Response time The time the server or peer spent in processing of the request and waiting before sending the response.
Jitter asymmetry The estimated asymmetry of network jitter on the path to the source. The asymmetry can be between -0.5 and 0.5. A negative value means the delay of packets sent to the source is more variable than the delay of packets sent from the source back.
NTP tests Results of RFC 5905 tests 1 through 3, 5 through 7, and tests for maximum delay, delay ratio, delay dev ratio, and synchronisation loop.
Interleaved This shows if the response was in the interleaved mode.
Authenticated This shows if the response was authenticated.
TX timestamping The source of the local transmit timestamp. Valid values are Daemon, Kernel, and Hardware.
RX timestamping The source of the local receive timestamp.
Total TX The number of packets sent to the source.
Total RX The number of all packets received from the source.
Total valid RX The number of valid packets received from the source.
add peer name [option]... The add peer command allows a new NTP peer to be added whilst chronyd is running.
Following the words add peer, the syntax of the following parameters and options is identical to that for the peer directive in the configuration file.
An example of using this command is shown below.
add peer foo.example.net minpoll 6 maxpoll 10 key 25
add pool name [option]... The add pool command allows a pool of NTP servers to be added whilst chronyd is running.
Following the words add pool, the syntax of the following parameters and options is identical to that for the pool directive in the configuration file.
An example of using this command is shown below:
add pool foo.example.net maxsources 3 iburst
add server name [option]... The add server command allows a new NTP server to be added whilst chronyd is running.
Following the words add server, the syntax of the following parameters and options is identical to that for the server directive in the configuration file.
add server foo.example.net minpoll 6 maxpoll 10 key 25
delete address The delete command allows an NTP server or peer to be removed from the current set of sources.
burst good/max [mask/masked-address], burst good/max [masked-address/masked-bits], burst good/max [address] The burst command tells chronyd to make a set of measurements to each of its NTP sources over a short duration (rather than the usual periodic measurements that it makes). After such a burst, chronyd will revert to the previous state for each source. This might be either online, if the source was being periodically measured in the normal way, or offline, if the source had been indicated as being offline. (A source can be switched between the online and offline states with the online and offline commands.)
The mask and masked-address arguments are optional, in which case chronyd will initiate a burst for all of its currently defined sources.
The arguments have the following meaning and format:
good This defines the number of good measurements that chronyd will want to obtain from each source. A measurement is good if it passes certain tests, for example, the round trip time to the source must be acceptable. (This allows chronyd to reject measurements that are likely to be bogus.)
max This defines the maximum number of measurements that chronyd will attempt to make, even if the required number of good measurements has not been obtained.
mask This is an IP address with which the IP address of each of chronyd’s sources is to be masked.
masked-address This is an IP address. If the masked IP address of a source matches this value then the burst command is applied to that source.
masked-bits This can be used with masked-address for CIDR notation, which is a shorter alternative to the form with mask.
address This is an IP address or a hostname. The burst command is applied only to that source.
If no mask or masked-address arguments are provided, every source will be matched.
An example of the two-argument form of the command is:
burst 2/10
This will cause chronyd to attempt to get two good measurements from each source, stopping after two have been obtained, but in no event will it try more than ten probes to the source.
Examples of the four-argument form of the command are:
burst 2/10 255.255.0.0/1.2.0.0 burst 2/10 2001:db8:789a::/48
In the first case, the two out of ten sampling will only be applied to sources whose IPv4 addresses are of the form 1.2.x.y, where x and y are arbitrary. In the second case, the sampling will be applied to sources whose IPv6 addresses have first 48 bits equal to 2001:db8:789a.
Example of the three-argument form of the command is:
burst 2/10 foo.example.net
maxdelay address delay This allows the maxdelay option for one of the sources to be modified, in the same way as specifying the maxdelay option for the server directive in the configuration file.
maxdelaydevratio address ratio This allows the maxdelaydevratio option for one of the sources to be modified, in the same way as specifying the maxdelaydevratio option for the server directive in the configuration file.
maxdelayratio address ratio This allows the maxdelayratio option for one of the sources to be modified, in the same way as specifying the maxdelayratio option for the server directive in the configuration file.
maxpoll address maxpoll The maxpoll command is used to modify the maximum polling interval for one of the current set of sources. It is equivalent to the maxpoll option in the server directive in the configuration file.
Note that the new maximum polling interval only takes effect after the next measurement has been made.
minpoll address minpoll The minpoll command is used to modify the minimum polling interval for one of the current set of sources. It is equivalent to the minpoll option in the server directive in the configuration file.
Note that the new minimum polling interval only takes effect after the next measurement has been made.
minstratum address minstratum The minstratum command is used to modify the minimum stratum for one of the current set of sources. It is equivalent to the minstratum option in the server directive in the configuration file.
offline [address], offline [masked-address/masked-bits], offline [mask/masked-address] The offline command is used to warn chronyd that the network connection to a particular host or hosts is about to be lost, e.g. on computers with intermittent connection to their time sources.
Another case where offline could be used is where a computer serves time to a local group of computers, and has a permanent connection to true time servers outside the organisation. However, the external connection is heavily loaded at certain times of the day and the measurements obtained are less reliable at those times. In this case, it is probably most useful to determine the gain or loss rate during the quiet periods and let the whole network coast through the loaded periods. The offline and online commands can be used to achieve this.
There are four forms of the offline command. The first form is a wildcard, meaning all sources (including sources that do not have a known address yet). The second form allows an IP address mask and a masked address to be specified. The third form uses CIDR notation. The fourth form uses an IP address or a hostname. These forms are illustrated below.
offline offline 255.255.255.0/1.2.3.0 offline 2001:db8:789a::/48 offline foo.example.net
The second form means that the offline command is to be applied to any source whose IPv4 address is in the 1.2.3 subnet. (The host’s address is logically and-ed with the mask, and if the result matches the masked-address the host is processed.) The third form means that the command is to be applied to all sources whose IPv6 addresses have their first 48 bits equal to 2001:db8:789a. The fourth form means that the command is to be applied only to that one source.
The wildcard form of the address is equivalent to:
offline 0.0.0.0/0.0.0.0 offline ::/0
online [address], online [masked-address/masked-bits], online [mask/masked-address] The online command is opposite in function to the offline command. It is used to advise chronyd that network connectivity to a particular source or sources has been restored.
The syntax is identical to that of the offline command.
onoffline The onoffline command tells chronyd to switch all sources that have a known address to the online or offline status according to the current network configuration. A source is considered online if it is possible to send requests to it, i.e. a network route to the source is present.
polltarget address polltarget The polltarget command is used to modify the poll target for one of the current set of sources. It is equivalent to the polltarget option in the server directive in the configuration file.
refresh The refresh command can be used to force chronyd to resolve the names of configured sources to IP addresses again, e.g. after suspending and resuming the machine in a different network.
Sources that stop responding will be replaced with newly resolved addresses automatically after 8 polling intervals, but this command can still be useful to replace them immediately and not wait until they are marked as unreachable.
reload sources The reload sources command causes chronyd to re-read all *.sources files from the directories specified by the sourcedir directive.
sourcename address The sourcename command prints the original hostname or address that was specified for an NTP source in the configuration file, or the add command. This command is an alternative to the -N option, which can be useful in scripts.
Note that different NTP sources can share the same name, e.g. servers from a pool.
Manual time input manual on, manual off, manual delete index, manual list, manual reset The manual command enables and disables use of the settime command, and is used to modify the behaviour of the manual clock driver.
The on form of the command enables use of the settime command.
The off form of the command disables use of the settime command.
The list form of the command lists all the samples currently stored in chronyd. The output is illustrated below.
210 n_samples = 1 #    Date  Time(UTC)    Slewed   Original   Residual ==================================================== 0 27Jan99 22:09:20       0.00       0.97       0.00
The columns are as as follows:
1. The sample index (used for the manual delete command).
2. The date and time of the sample.
3. The system clock error when the timestamp was entered, adjusted to allow for changes made to the system clock since.
4. The system clock error when the timestamp was entered, as it originally was (without allowing for changes to the system clock since).
5. The regression residual at this point, in seconds. This allows ‘outliers’ to be easily spotted, so that they can be deleted using the manual delete command.
The delete form of the command deletes a single sample. The parameter is the index of the sample, as shown in the first column of the output from manual list. Following deletion of the data point, the current error and drift rate are re-estimated from the remaining data points and the system clock trimmed if necessary. This option is intended to allow ‘outliers’ to be discarded, i.e. samples where the administrator realises they have entered a very poor timestamp.
The reset form of the command deletes all samples at once. The system clock is left running as it was before the command was entered.
settime time The settime command allows the current time to be entered manually, if this option has been configured into chronyd. (It can be configured either with the manual directive in the configuration file, or with the manual command of chronyc.)
It should be noted that the computer’s sense of time will only be as accurate as the reference you use for providing this input (e.g. your watch), as well as how well you can time the press of the return key.
Providing your computer’s time zone is set up properly, you will be able to enter a local time (rather than UTC).
The response to a successful settime command indicates the amount that the computer’s clock was wrong. It should be apparent from this if you have entered the time wrongly, e.g. with the wrong time zone.
The rate of drift of the system clock is estimated by a regression process using the entered measurement and all previous measurements entered during the present run of chronyd. However, the entered measurement is used for adjusting the current clock offset (rather than the estimated intercept from the regression, which is ignored). Contrast what happens with the manual delete command, where the intercept is used to set the current offset (since there is no measurement that has just been entered in that case).
The time is parsed by the public domain getdate algorithm. Consequently, you can only specify time to the nearest second.
Examples of inputs that are valid are shown below:
settime 16:30 settime 16:30:05 settime Nov 21, 2015 16:30:05
For a full description of getdate, see the getdate documentation (bundled, for example, with the source for GNU tar).
NTP access accheck address This command allows you to check whether client NTP access is allowed from a particular host.
Examples of use, showing a named host and a numeric IP address, are as follows:
accheck foo.example.net accheck 1.2.3.4 accheck 2001:db8::1
This command can be used to examine the effect of a series of allow, allow all, deny, and deny all commands specified either via chronyc, or in chronyd’s configuration file.
clients [-p packets] [-k] [-r] This command shows a list of clients that have accessed the server, through the NTP, command, or NTS-KE port. It does not include accesses over the Unix domain command socket.
The -p option specifies the minimum number of received NTP or command packets, or accepted NTS-KE connections, needed to include a client in the list. The default value is 0, i.e. all clients are reported. With the -k option the last four columns will show the NTS-KE accesses instead of command accesses. If the -r option is specified, chronyd will reset the counters of received and dropped packets or connections after reporting the current values.
An example of the output is:
Hostname                      NTP   Drop Int IntL Last     Cmd   Drop Int  Last =============================================================================== localhost                       2      0   2   -   133      15      0  -1     7 foo.example.net                12      0   6   -    23       0      0   -     -
Each row shows the data for a single host. Only hosts that have passed the host access checks (set with the allow, deny, cmdallow and cmddeny commands or configuration file directives) are logged. The intervals are displayed as a power of 2 in seconds.
1. The hostname of the client.
2. The number of NTP packets received from the client.
3. The number of NTP packets dropped to limit the response rate.
4. The average interval between NTP packets.
5. The average interval between NTP packets after limiting the response rate.
6. Time since the last NTP packet was received
7. The number of command packets or NTS-KE connections received/accepted from the client.
8. The number of command packets or NTS-KE connections dropped to limit the response rate.
9. The average interval between command packets or NTS-KE connections.
10. Time since the last command packet or NTS-KE connection was received/accepted.
serverstats The serverstats command displays how many valid NTP and command requests, and NTS-KE connections, chronyd operating as a server received from clients, and how many of them were dropped due to rate limiting. It also displays how many client log records were dropped due to the memory limit configured by the clientloglimit directive and how many of the NTP requests (from those which were not dropped) were authenticated. An example of the output is shown below.
NTP packets received       : 1598 NTP packets dropped        : 8 Command packets received   : 19 Command packets dropped    : 0 Client log records dropped : 0 NTS-KE connections accepted: 3 NTS-KE connections dropped : 0 Authenticated NTP packets  : 189
allow [all] [subnet] The effect of the allow command is identical to the allow directive in the configuration file.
The syntax is illustrated in the following examples:
allow 1.2.3.4 allow all 3.4.5.0/24 allow 2001:db8:789a::/48 allow 0/0 allow ::/0 allow allow all
deny [all] [subnet] The effect of the allow command is identical to the deny directive in the configuration file.
deny 1.2.3.4 deny all 3.4.5.0/24 deny 2001:db8:789a::/48 deny 0/0 deny ::/0 deny deny all
local [option]..., local off The local command allows chronyd to be told that it is to appear as a reference source, even if it is not itself properly synchronised to an external source. (This can be used on isolated networks, to allow one computer to be a master time server with the other computers slaving to it.)
The first form enables the local reference mode on the host. The syntax is identical to the local directive in the configuration file.
The second form disables the local reference mode.