Updating the System Time in Raspian / Ubuntu

To check and update the system time via SSH on your Raspberry Pi (or any other Linux-based system), you can use the following steps:

1. Connect to your Raspberry Pi via SSH.
   
Open a terminal on your computer and type:   

ssh [your_username]@[your_raspberry_pi_ip_address]

Replace `[your_username]` with your actual username on the Raspberry Pi, and `[your_raspberry_pi_ip_address]` with the device's IP address.

2. Check the current system time.
   
Once you're connected, you can check the current system date and time by typing:  

sudo date

3. Update the system time.
   
   If the system time is incorrect, you can set it manually using the `date` command followed by a string representing the new date and time. For example:   

sudo date MMDDhhmmCCYY.ss

   This is the format:
   - `MM` is the two-digit month.
   - `DD` is the two-digit day.
   - `hh` is two digits of hour (00 through 23).
   - `mm` is two digits of minute (00 through 59).
   - `CC` is the first two digits of the year (the century).
   - `YY` is the last two digits of the year.
   - `.ss` is two digits of seconds.

Here is an example command that would set the date to April 12, 2024, at 9:18 AM:   

sudo date 041209182024.00

4. Set the timezone (if necessary).

 If you also need to set the correct timezone, you can use the `timedatectl` command:   

sudo timedatectl set-timezone [Your_Timezone]

Replace `[Your_Timezone]` with your actual timezone. You can list all available timezones with:

sudo timedatectl set-timezone America/Chicago

sudo timedatectl list-timezones

5. Synchronize time with an NTP server.

If you want to ensure the system maintains accurate time, you might want to install and enable `NTP` (Network Time Protocol). You can install `ntp` with:

sudo apt-get update
sudo apt-get install ntp

 Once installed, it should start automatically and synchronize the time. You can check its status with:

sudo systemctl status ntp

By following these steps, you should be able to check and update your system time via SSH. If the Raspberry Pi is connected to the internet, it is recommended to use NTP to keep the system time accurate automatically.