[LEAPSECS] 2008-12-31T23:59:60Z

Zefram zefram at fysh.org
Wed Dec 24 06:02:11 EST 2008

Sanjeev Gupta wrote:

>Any help on how to use a Linux PC driving a large monitor/LCD projector to

>show a group of school children the leap second?

Firstly, for the Linux clock to indicate the leap second at all, you
*must* be NTP-synchronised. As long as you have a net connection, there
are plenty of public NTP servers to synch to. Check that your clock is
actually synched. The "rv" command in ntpq should show "leap_add_sec"
near the start of its output, indicating that it knows about the
upcoming leap.

The difficult bit is that hardly any Unix software is leap-second-aware.
Most clock programs will glitch. I wrote one that will tick through
leaps correctly: <http://www.fysh.org/~zefram/time/purchron>.
I suggest running it with a display formula such as

purchron produces plain text output. To display it full screen you'll
want to run it in an xterm (or similar) with a very big font.


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