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user2155009
Asked: 2013-07-23 12:22:57 +0800 CST

Setting timezone from terminal

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I want to change the timezone of the system clock from the terminal.

This can be done with

tzselect

"which opens a gui in terminal"

or

sudo cp /usr/share/zoneinfo/Europe/London /etc/localtime

"which will set to gmt"

But is there a way to set time zone with just the offset ie.-1 or +5 etc?

I need to do this as I'm writing an application to adjust timeoffset or report logs and the only info I have is the user IP. I can use a webapp to find the location of the IP, but then I need to set offset which would be easy IF I could just get the offset of the location, but if I need to find zone and city it would be a real pain.

If anyone knows the answer to how to set system clock with +/-hour would be great.

timezone

8 Answers

  1. To change time zone from terminal, just press Ctrl+Alt+T on your keyboard to open Terminal. When it opens, run the command(s) below:

    sudo dpkg-reconfigure tzdata

    Once open, just follow the screens to change the time zone.

    • 349

  2. You can also use the new timedatectl to set the time in 14.04.

    sudo timedatectl set-timezone America/New_York
    • 185

  3. I realize this thread is a bit dated, but I was looking for a better solution because I needed to automatically set the timezone in a VM after a user downloads it from our website and deploys it. Here's what I ended up with:

    echo "Setting TimeZone..."
export tz=`wget -qO - http://geoip.ubuntu.com/lookup | sed -n -e 's/.*<TimeZone>\(.*\)<\/TimeZone>.*/\1/p'` &&  timedatectl set-timezone $tz
export tz=`timedatectl status| grep Timezone | awk '{print $2}'`
echo "TimeZone set to $tz"

    This will query geoip.ubuntu.com from the server once it is started on the new network (my script checks for connectivity first course) and then set the server's timezone based on the response.

    The "wget -q0 -" tells wget to output only the results to stdout which is then piped to the $tz variable.

    Hope it helps someone!

    • 25

  4. You can use the GMT±x files in /usr/share/zoneinfo/Etc.

    sudo ln -fs /usr/share/zoneinfo/Etc/GMT$offset /etc/localtime
    • 22

  5. TL;DR /etc/localtime is a symbolic link that points to a file in /usr/share/zoneinfo/Continent/City. By altering where it points you can alter your timezone.

    In order to change timezone, remove the /etc/localtime and assign symbolic link to your desired city. For instance, ls -l /etc/localtime reports that this file points to /usr/share/zoneinfo/America/Denver. To change it to New York, I do

    1. sudo rm /etc/localtime
    2. sudo ln -s /usr/share/zoneinfo/America/New_York /etc/localtime
    3. Wait a minute for my clock to get updated

    The screenshot bellow shows the steps and confirmation from timedatectl

    enter image description here

    • 16

  6. The easy way to update the timezone is to use sudo dpkg-reconfigure tzdata. But this isn't so easily scripted.

    If you want to set the timezone explicitly via a script (e.g. for setting up a VM), here's a recipe:

    Set a variable for the timezone you want, e.g. one of

    tz=Europe/London
tz=America/Anchorage
tz=Etc/GMT+6

    Valid values are the directories and filenames under /usr/share/zoneinfo.

    Then simply

    sudo cp -vf /usr/share/zoneinfo/$tz /etc/localtime
echo $tz | sudo tee /etc/timezone

    Note that both /etc/localtime and /etc/timezone must be consistent.

    Probably now reboot to get all your services updated too (e.g. cron).

    • 12

  7. Here's the method I use, which is US-centric as I don't need to worry about non-US time zones.

    If I need to determine the current time zone, I either do: 

    cat /etc/timezone

    or 

    sudo hwclock --show

    I then do: 

    timedatectl set-timezone <_designation_>

    where <_designation_> is one of the following:

    US/Eastern
    US/Central
    US/Mountain
    US/Pacific
    US/Alaska
    US/Aleutian
    US/Arizona
    US/East-Indiana
    US/Hawaii
    US/Indiana-Starke
    US/Michigan
    US/Pacific-New
    US/Samoa

    E.G.: 

    timedatectl set-timezone US/Eastern

    Other timezone designations can be found here: https://en.wikipedia.org/wiki/List_of_tz_database_time_zones

    • 6

  8. You cannot do this unless you select the time zone file you want to correspond to each time zone offset.

    Some answers suggested using the files in /usr/share/zoneinfo/Etc, but the problem with these is that they are DST agnostic.

    So unless you pick some time zone configuration to match each offset, or you don't care about DST, there is no way to do it generically.

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