On Tue, Nov 2, 2010 at 1:48 PM, Chris Jackson <c.jack...@shadowcat.co.uk>wrote:
> Rodolfo Medina wrote: > > > Hallo. > > > > Last sunday, in my time zone (Rome), clocks were got back by one hour. I > > noticed that my Debian Lenny had done so automatically, but files > timestamps > > were also took back by one hour, which is not what we want. > > > File timestamps are (or at least should be) stored in UTC. It's the > display of them that's affected. Setting the TZ variable may help: > > export TZ=UTC > > Timestamps stored _in_ files (for example log files) are taken from > system time, that stored in /etc/localtime. You might want to set that > to UTC and, where required, alter the displayed time using the TZ > variable, rather than running system time on something with DST, since > it can cause problems with timestamps within log files etc. being > duplicated around the time of the change. > > cp /usr/share/zoneinfo/UTC /etc/localtime > > Or, you may wish to use a nearer-local non-DST timestamp: > > cp /usr/share/zoneinfo/Etc/GMT-1 /etc/localtime > > Personally I find using UTC/GMT on all our systems, wherever based, as > system time the simplest, and managing the displayed time using TZ as > applicable. It means to read log files you need to convert, but at least > it's in only one direction, wherever you are. > > You could also make a test to see what happen. touch /tmp/test ls /tmp/test date --utc --reference /tmp/test The output will be similar to: $ ls -al /tmp/test -rw-r--r-- root root 0 2010-11-02 14:07 /tmp/test $date --utc --reference /tmp/test Tue Nov 2 13:07:23 UTC 2010 I'am in UTC+1 (currently normal time in Europe). If you change you timezone setting, you will see, that the ls output will be show based upon your timezone. The date command will still show the create time of the file in UTC, and this will not be changed. Timestamps are stored _in_ the file based on UTC like Chris explained. Mario -- http://www.n0r1sk.com
