Software & AppsOperating SystemLinux

How To Get Date&Time Using Curl Command?

Ubuntu 5

In the world of system administration, the ability to fetch and manipulate date and time information is crucial. One of the ways to do this is by using the curl command. This article will walk you through how to get date and time using the curl command.

Quick Answer

To get the date and time using the curl command, you can send a HEAD request to a server and extract the date from the response headers. You can then use the date command to format the date and time as desired. Finally, you can set the system date and time using the formatted date.

Introduction to Curl

Curl is a powerful tool that allows you to transfer data from or to a server using various protocols, including HTTP, HTTPS, FTP, and more. It’s widely used in command lines or scripts to transfer data. In this case, we’ll be using curl to fetch the date and time from a server’s response headers.

Fetching Date and Time

To fetch the date and time, we will send a HEAD request to a server and extract the date from the response headers. Here’s the command:

dateFromServer=$(curl -I 'https://example.com' 2>/dev/null | grep -i '^date:' | sed 's/^[Dd]ate: //g')

Let’s break down this command:

  • curl -I 'https://example.com' sends a HEAD request to the specified URL. The -I option tells curl to only fetch the headers.
  • 2>/dev/null redirects any error messages to /dev/null, effectively discarding them.
  • grep -i '^date:' searches the response headers for a line that starts with ‘date:’ (case-insensitive due to the -i option).
  • sed 's/^[Dd]ate: //g' uses the sed command to remove the ‘Date: ‘ prefix from the line, leaving only the date and time.

The dateFromServer variable will now contain the date and time in a format like “Sat, 29 Oct 2022 21:30:49 GMT”.

Formatting the Date and Time

To format the date and time, we can use the date command:

formattedDate=$(date -d "$dateFromServer" +"%d%m%Y%H%M%S")

Here’s what this command does:

  • date -d "$dateFromServer" parses the date from the dateFromServer variable.
  • +"%d%m%Y%H%M%S" formats the date according to the desired format “DDMMYYYYHHMMSS”.

The formattedDate variable will now contain the date and time in the desired format.

Setting the System Date and Time

To set the system date and time, use the following command:

sudo date -s "$formattedDate"

This command sets the system date and time using the formattedDate value. Note that this command requires root privileges (sudo) to modify the system time.

Alternative: Using NTP

If your PC’s RTC (Real Time Clock) is not working, you can retrieve the date and time from a remote server using NTP (Network Time Protocol). NTP servers provide accurate time synchronization over the internet. Here’s an example using the ntpdate command:

sudo ntpdate -u pool.ntp.org

This command retrieves the date and time from the NTP server pool.ntp.org and sets the system time accordingly. Again, root privileges (sudo) are required to modify the system time.

Conclusion

In this article, we’ve explored how to get date and time using the curl command. We’ve learned how to fetch, format, and set the date and time, and even how to synchronize time using NTP.

Remember to replace https://example.com with the URL of a server that provides the date and time information, and adjust the NTP server if needed.

Also, it’s important to have a reliable internet connection for these methods to work properly. Happy time fetching!

What is the purpose of the `curl` command?

The curl command is used to transfer data from or to a server using various protocols like HTTP, HTTPS, FTP, etc.

How can I fetch the date and time using `curl`?

To fetch the date and time using curl, you can send a HEAD request to a server and extract the date from the response headers. The command to do this is dateFromServer=$(curl -I 'https://example.com' 2>/dev/null | grep -i '^date:' | sed 's/^[Dd]ate: //g').

How can I format the fetched date and time?

You can format the fetched date and time using the date command. For example, to format it as "DDMMYYYYHHMMSS", you can use the command formattedDate=$(date -d "$dateFromServer" +"%d%m%Y%H%M%S").

Can I set the system date and time using the `curl` command?

No, the curl command is used to fetch data and does not have the capability to directly set the system date and time. You would need to use other commands like date or ntpdate to set the system date and time.

How can I set the system date and time?

To set the system date and time, you can use the date command with the desired date and time format. For example, sudo date -s "$formattedDate" sets the system date and time using the value stored in the formattedDate variable.

What is NTP and how can I use it to synchronize time?

NTP (Network Time Protocol) is a protocol used for time synchronization over the internet. If your PC’s RTC is not working, you can retrieve the date and time from a remote NTP server. For example, sudo ntpdate -u pool.ntp.org retrieves the date and time from the NTP server pool.ntp.org and sets the system time accordingly.

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