-*- mode: outline; coding: utf-8; fill-column: 80 -*-

* System timer and system time.

** Windows.

Windows assume that system timer display locale time.

** Debian.

UTC=no - system timer display locale time, UTC=yes - UTC time.

  $ cat /etc/default/rcS
  UTC=no
or
  UTC=yes

If system dual boot with Windows you must set UTC=no.

* Getting current date/time.

  $ date +"%Y-%m-%d %H:%M:%S"

* Setting current date/time.

  $ sudo date --set="2009-02-22 12:12:00" +"%Y-%m-%d %H:%M:%S"

Or set utc time:

  $ sudo date --utc --set="2009-02-22 12:12:00" +"%Y-%m-%d %H:%M:%S"

May be prefer use ntpdate(8) command.

* Get timezone.

System wide configuration:

  $ cat /etc/timezone

* Get list of supported timezone.

  $ tzselect

* Set timezone.

  $ sudo tzconfig
...

Or using tzselect:

  $ sudo tzselect
...

** Debian Lenny.

  $ sudo dpkg-reconfigure tzdata

* About timestamp.

  http://en.wikipedia.org/wiki/Timestamp
  http://en.wikipedia.org/wiki/Unix_time
  http://en.wikipedia.org/wiki/Leap_second

** Get timestamp.

Current timestamp:

  $ date +%s

Timestamp for specific date/time:

  $ date -d '2010-12-11' +%s
  $ date -d '2010-12-11 23:59:59' +%s

** Convert unix timestamp to date.

  $ date -d '1970-01-01 + 1234567890 seconds'