How do I set time and date from the Internet?

Question

How do I retrieve the date from the Internet and set my computer's clock, from the command line?

Solution 1

You can use :

sudo dpkg-reconfigure tzdata

for configuring your timezone .

For updating time and date from internet use the following :

Install

If ntpd is not installed use any one of the following command to install ntpd:

• For RPM based:

  yum install ntp 
  

• For Debian based:

  sudo apt-get install ntp
  

Configuration

You should at least set following parameter in /etc/ntp.conf config file: server

For example, open /etc/ntp.conf file using vi text editor:

  # vi /etc/ntp.conf

Locate server parameter and set it as follows:

  server pool.ntp.org

Save the file and restart the ntpd service:

  # /etc/init.d/ntpd start

You can synchronize the system clock to an NTP server immediately with following command:

  # ntpdate pool.ntp.org

*For setting the time and date manually use the following syntax:

 date --set="STRING"

For example, set new data to 2 Oct 2006 18:00:00, type the following command as root user:

# date -s "2 OCT 2006 18:00:00"

OR

# date --set="2 OCT 2006 18:00:00"

You can also simplify format using following syntax:

# date +%Y%m%d -s "20081128"

To set time use the following syntax:

# date +%T -s "10:13:13"

Where,

10: Hour (hh) 13: Minute (mm) 13: Second (ss)

Use %p locale’s equivalent of either AM or PM, enter:

# date +%T%p -s "6:10:30AM"

# date +%T%p -s "12:10:30PM"

Solution 2

A small code I found to update your time in case you don't want to install anything just to update the date. :)

sudo date -s "$(wget --method=HEAD -qSO- --max-redirect=0 google.com 2>&1 | grep Date: | cut -d' ' -f2-7)"

This command assumes that the "Date" header in the response to the wget request has the format Date: Wed, 05 Jan 2022 10:53:35 GMT. The format of the header has changed in the past. You can check whether date correctly understands the string before actually setting the time by running

$ date -d "$(wget --method=HEAD -qSO- --max-redirect=0 google.com 2>&1 | grep Date: | cut -d' ' -f2-7)"
Mon Jan 10 11:40:46 AM CET 2022

The wget command may be replaced by curl -Is --max-redirs 0 google.com.

Note that --method=HEAD is used because it seems that GET responses may be cached (with an old Date header) while HEAD responses are fresh.

Solution 3

I use this:

sudo ntpd -qg; sudo hwclock -w

first tell ntpd to just set the time and stop after that with -q. Also, in case a your clock has a big error we need to tell ntpd to also adjust in that case with -g. Finally write the clock to hardware to preserve the changes when rebooting with hwclock -w (-w for setting hardwareclock to current system time, there is a difference).

Solution 4

Use ntpdate, ntpd, or Chrony to connect to a NTP server.

Solution 5

Some distributions are shipping rdate for that purpose. Basic usage:

# just query
bash-4.2$ rdate pool.ntp.org
rdate: [pool.ntp.org]   Wed Jun 12 11:05:40 2013

# set system time
bash-4.2$ rdate -s pool.ntp.org

View more solutions

Comments

[corsel]

I do not understand downvotes. Simple questions are what make a community powerful. For example see this

[Anthon]

When I hover above a question's down arrow with my mouse I see: "This question does not show any research effort; it is unclear or not useful". I would be tempted to downvote your question based on the first (no indication of what you found), the second (no indication on what specific platform you are working on, and why this has to be commandline (instead of the usual time daemon)) and the third (most *nix users will have some time daemon installed by default).

[l0b0]

+1 I do not understand the downvotes either, simply because this is something which has bugged me many times before, and it seems impossible to find anything concise and useful about this specific theme.

[sunnysideup]

@Mohsen I didn't downvote but the difference to the question you linked is that there is no switch in ruby while you can set directly the date via date -s (as shown in the manpage), or use any of the commands described below...

[Anthon]

possible duplicate of Trying to set date on a Linux based machine from another machine

[Gilles 'SO- stop being evil']

@Anthon I disagree: that question is about a small device with BusyBox, which makes the generic advice “use NTP” not necessarily applicable

[dfc]

The example I saw was the highest voted comment: "This is amazing how this question is upvoted but doesn't show any search effort." You could find the answer if you type the title of your question plus your operating system into any search box google/ddg/bing.

[Ciro Santilli Путлер Капут 六四事]

related: superuser.com/questions/635020/…

[Anthon]

Although the date information seems all valid, it does not take the requirement from the internet from the title of the OP into account anywhere.

[tusharmakkar08]

I believe that tzdata (time zone data) package synchronizes the data from internet only. Correct me if I am wrong .

[Anthon]

tzdata is information about timezones and daylight saving time (start, end, epoch) not the actual date and time. Of course that is handy to know how to get to your local time based on knowledge of your timezone and a UTC time, but you still need to retrieve the latter from the internet.

[tusharmakkar08]

@Anthon : I have edited my answer correspondingly.Thank You.

[Ulises Sánchez]

i tend to do this with a "&&" instead of the semicolon so that if the first command should fail (e.g. network connectivity down) the second command is short-circuited

[dfc]

What distro uses dpkg AND yum?

[andrewtweber]

Way better and easier than ntp

[tusharmakkar08]

No one (AFAIK). I answered it while I was shifting from Linux mint to fedora. Updating the answer correspondingly.

[MatthewLee]

pool.ntp.org now refuses connections from rdate. time.nist.gov works. Also once you have set the system time, you should set the hardware clock as well by running hwclock -w to set it to the system time. You can then verify it is correct by running hwclock -r

[Kodiak]

I use google.in to get the current time for my timezone (INDIA).

[user202729]

Note the trailing Z which indicates that the time is given in zulu time zone, so no special timezone manipulation should be needed if the computer timezone is set correctly.

[Prajwal]

When I change from Windows to Linux, my laptops time gets changed. $ sudo ntpdate pool.ntp.org; resets it.

[Monsieur Pierre Dunn]

After that don't forget to change HW clock with sudo hwlock --systohc.

[Vitaly Zdanevich]

This is wrong after PM.

[matt wilkie]

I would switch the order of the test and set code examples in the answer, as it's better to test first. ;-) For me I needed to change the cut args to -f4-10, so date -d "$(wget --method=HEAD -qSO- --max-redirect=0 google.com 2>&1 | grep Date: | cut -d' ' -f4-10)"