Dreamhost seems to think that we like PDT, despite being in the Midwest. How do I change the timezone?
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4 Answers
A tool I found to be easier to use is dpkg-reconfigure. Use:
sudo dpkg-reconfigure tzdata
You will be given a multitude of choices, including some that are not included in tzselect.
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A benefit of doing it this way is that you are doing it in a reproduceable way and limit the chances for doing something wrong like putting in a timezone that does not exist.– MoggetCommented Apr 21, 2013 at 17:56
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1This is good stuff, but if you need a non-interactive (and therefore scriptable) option, see my answer below.– mc0eCommented Jul 21, 2015 at 5:33
This is presumably a bit late for the OP, and more intended for other searchers who arrive here.
If you need a non-interactive solution, try this solution from changing timezone with dpkg-reconfigure tzdata and debconf-set-selections
echo "Europe/Zurich" > /etc/timezone
dpkg-reconfigure -f noninteractive tzdata
You can figure out your timezone by poking around in /usr/share/zoneinfo. In fact the dpkg-reconfigure command above copies the appropriate file from there to /etc/localtime. I used to just do that manually, and it seems to work fine.
Don't be too surprised if long running processes don't pick up the change. eg Apache log timestamps come to mind. Consider whether that matters, and hence whether you need to restart running processes or even reboot.
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3Beware that for this to work, it's a requirement that
/etc/localtimedoes not already exist. If it exists and is a softlink to/usr/share/zoneinfo/whatever, it's taken as base and it is/etc/localtimethat is updated accordingly, overwriting your changes. Commented Jul 23, 2018 at 7:15
To edit it non interactively on recent Debian and Ubuntu versions (Stretch/Xenial etc.), you need to remove /etc/localtime as well, otherwise /etc/timezone will be overwritten.
echo 'Europe/Zurich' > /etc/timezone
rm /etc/localtime
dpkg-reconfigure -f noninteractive tzdata
This answer is based on mc0e' answer. I can not add a comment with my reputation.
TL;DR
echo "TZ=Etc/UTC" >> /etc/environment
tzconfig
where Etc/UTC is your preferred timezone you found using tzselect.
Longer version
When you're using
dpkg-reconfigure tzdata
the timezone information is not kept after reboot. You can verify your settings with
diff -s /etc/localtime /usr/share/zoneinfo/`cat /etc/timezone`
If you're only updating /etc/timezone, the update won't be consistent with /etc/localtime, thus it's better to execute
tzconfig
Use tzselect to find out which time zones actually exists (or simply browse /usr/share/zoneinfo directory).
In POSIX systems the TZ should take precedence before /etc/localtime:
export TZ='Europe/Berlin'
$ date
Tue Apr 10 08:51:03 CEST 2018
export TZ='Pacific/Efate'
$ date
Tue Apr 10 18:28:33 +11 2018
Using directly TZ can save you many system calls as frequently used date/time related functions has to access filesystem each time some program asks for current date. It's a micro-optimization, but quite simple one.
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Are you positive exporting
TZin your profile file creates a symlink? That does not sound true at all in my experience. Perhaps you meant "Also make sure to create the symlink..."? Commented Apr 9, 2018 at 16:37 -
1@amn No, that won't create a symlink, I've tried to clarify that. But
$TZvariable is read byglibcfunctions: gnu.org/software/libc/manual/html_node/TZ-Variable.html– TombartCommented Apr 10, 2018 at 7:01 -
shouldn't it be
echo "TZ=Etc/UTC" >> /etc/environment? you're missingTZ=part... (if case someone is still running ancient debian versions). Also, noninteractive stuff like daemons would still use/etc/localtimeversion instead of one set inTZ... Commented Sep 27, 2018 at 12:41 -