tz2alt(8): Monitors daylight savings time changes and publishes them to PTP stack


ts2alt [ -hmqv ] [ -f conf ] [ -k key ] [ -p period ] [ -w window ] [ -z timezone ] [ long-options ] …


tz2alt leverages the local time zone database to monitor for changes in daylight savings time and publishes the pending changes to the PTP stack.


-f config

Read configuration from the specified file. No configuration file is read by default.


Displays the command line help summary.

-l print-level

Sets the maximum syslog level of messages which should be printed or sent to the system logger. The default is 6 (LOG_INFO).


Prints log messages to the standard output.


Prevents sending log messages to the system logger.


Prints the software version and exits.


Each and every configuration file option (see below) may also appear as a “long” style command line argument. For example, the use_syslog option may be set using either of these two forms.

--use_syslog 1


Option values given on the command line override values in the global section of the configuration file.


The configuration file is divided into sections. Each section starts with a line containing its name enclosed in brackets and it follows with settings. Each setting is placed on a separate line, it contains the name of the option and the value separated by whitespace characters. Empty lines and lines starting with # are ignored.



The domain attribute of the local clock. The default is 0.


The path to the current leap seconds definition file. In a Debian system this file is provided by the tzdata package and can be found at /usr/share/zoneinfo/leap-seconds.list. If a leapfile is configured it will be reloaded if modified. The default is an empty string, which causes the program to use a hard coded table that reflects the known leap seconds on the date of the software’s release.


The maximum logging level of messages which should be printed. The default is 6 (LOG_INFO).


The tag which is added to all messages printed to the standard output or system log. If the tag contains the string "{level}", it will be replaced with the log level of the message as a number. The default is an empty string (which cannot be set in the configuration file as the option requires an argument).


The transport specific field. Must be in the range 0 to 255. The default is 0.


Print messages to the system log if enabled. The default is 1 (enabled).


Print messages to the standard output if enabled. The default is 0 (disabled).


Be cautious when sharing the same configuration file between ptp4l, phc2sys, and tz2alt. Keep in mind that values specified in the configuration file take precedence over the default values. If an option which is common to the other programs is set in the configuration file, then the value will be applied to all the programs using the file, and this might not be what is expected.

It is recommended to use separate configuration files for ptp4l, phc2sys, and tz2alt in order to avoid any unexpected behavior.