ALEVT-DATE(1) Teletext time ALEVT-DATE(1)NAME
alevt-date - display/set time received via Teletext
SYNOPSIS
alevt-date [options]
DESCRIPTION
alevt-date displays the time received from a Teletext source. It can be used to set the system time. The date is not interpreted (not
even transmitted on most channels). So it allows only adjustment of +/-12 hours. The default allowed adjustment is limited to +/-2 hours
(use -delta to change). Without the -set option it just displays the date in the format of the date(1) command.
OPTIONS
A summary of options is included below.
-set Set system time from time received via Teletext.
-delta seconds Maximum allowed adjustment made to the system time. The default is 7200 seconds (2 hours) and the maximum that may be
given is 12 hours.
-format string Format string to used to print the time. Look at strftime(3) for possible control sequences.
-vbi device Use the given device name. Default: /dev/vbi, /dev/vbi0, /dev/video0, /dev/dvb/adapter0/demux0 tried in this order.
-timeout seconds If the time can't be detected in seconds, the program is terminated with a SIGALRM.
-progname name Specifies the program name if using the DVB interface.
-pid pid Specifies the teletext PID if using the DVB interface.
--help Show summary of options.
--version Show version of program.
Before starting this program, you have to set the TV channel with another program like xawtv of set-tv.
Note: This program does not set the battery backed up clock of your computer. clock -w will do this.
The -progname or -pid option specifies the program or teletext PID if using the DVB interface.
If neither of these two options is used, alevt outputs informations about the currently accessible streams and uses the first of these PIDs
as default. This output contains the PIDs and names that can be used as an input for the -progname or -pid option in the context of the
currently chosen TV channel.
FILES
/dev/vbi*
/dev/dvb/adapter*/demux*
SEE ALSO alevt(1x), alevt-cap(1), strftime(3), date(1), clock(8).
BUGS
This program is just a toy. The time transmitted by the TV stations is more than inaccurate. Some are within a few seconds of your local
time reference but others are more then 15 minutes off. You've been warned. (And don't assume the pkt8/30 time is better. It's even
worse.)
No bug reports to <froese@gmx.de> *g*.
LINUX 1.6.2 ALEVT-DATE(1)
Check Out this Related Man Page
DATE(1) BSD General Commands Manual DATE(1)NAME
date -- display or set date and time
SYNOPSIS
date [-ajnu] [-d date] [-r seconds] [+format] [[[[[[CC]yy]mm]dd]HH]MM[.SS]]
DESCRIPTION
date displays the current date and time when invoked without arguments. Providing arguments will format the date and time in a user-defined
way or set the date. Only the superuser may set the date.
The options are as follows:
-a Use adjtime(2) to change the local system time slowly, maintaining it as a monotonically increasing function. -a implies -n.
-d date
Parse the provided human-described date and time and display the result without actually changing the system clock. (See
parsedate(3) for examples.)
-j Parse the provided canonical representation of date and time (described below) and display the result without actually changing the
system clock.
-n The utility timed(8) is used to synchronize the clocks on groups of machines. By default, if timed is running, date will set the
time on all of the machines in the local group. The -n option stops date from setting the time for other than the current machine.
-r seconds
Print out the date and time that is seconds from the Epoch.
-u Display or set the date in UTC (universal) time.
An operand with a leading plus (+) sign signals a user-defined format string which specifies the format in which to display the date and
time. The format string may contain any of the conversion specifications described in the strftime(3) manual page, as well as any arbitrary
text. A <newline> character is always output after the characters specified by the format string. The format string for the default display
is:
%a %b %e %H:%M:%S %Z %Y
If an operand does not have a leading plus sign, it is interpreted as a value for setting the system's notion of the current date and time.
The canonical representation for setting the date and time is:
CC The first two digits of the year (the century).
yy The second two digits of the year. If yy is specified, but CC is not, a value for yy between 69 and 99 results in a CC value
of 19. Otherwise, a CC value of 20 is used.
mm The month of the year, from 01 to 12.
dd The day of the month, from 01 to 31.
HH The hour of the day, from 00 to 23.
MM The minute of the hour, from 00 to 59.
SS The second of the minute, from 00 to 61.
Everything but the minutes is optional.
Time changes for Daylight Saving and Standard time and leap seconds and years are handled automatically.
ENVIRONMENT
The following environment variables affect the execution of date:
TZ The timezone to use when displaying dates. See environ(7) for more information.
FILES
/etc/localtime Symlink pointing to system's default timezone information file in /usr/share/zoneinfo directory.
/var/log/wtmp A record of date resets and time changes.
/var/log/messages A record of the user setting the time.
EXAMPLES
The command:
date '+DATE: %m/%d/%y%nTIME: %H:%M:%S'
will display:
DATE: 11/21/87
TIME: 13:36:16
The command:
date 8506131627
sets the date to ``June 13, 1985, 4:27 PM''.
The command:
date 1432
sets the time to 2:32 PM, without modifying the date.
DIAGNOSTICS
Exit status is 0 on success, 1 if unable to set the date, and 2 if able to set the local date, but unable to set it globally.
Occasionally, when timed(8) synchronizes the time on many hosts, the setting of a new time value may require more than a few seconds. On
these occasions, date prints: 'Network time being set'. The message 'Communication error with timed' occurs when the communication between
date and timed fails.
SEE ALSO adjtime(2), gettimeofday(2), settimeofday(2), parsedate(3), strftime(3), utmp(5), timed(8)
R. Gusella and S. Zatti, TSP: The Time Synchronization Protocol for UNIX 4.3BSD.
STANDARDS
The date utility is expected to be compatible with IEEE Std 1003.2 (``POSIX.2'').
BSD November 15, 2006 BSD