In Ubuntu 20.04, you can set or change the Fully Qualified Domain Name (FQDN) by following these steps: First, open the /etc/hosts file by running the following command: sudo nano /etc/hosts Locate the line that starts with 127.0.0.1 and change the hostname to your desired FQDN, for example: 127.0.0.1 localhost.localdomain mynewfqdn Next, you will need … Read more

Unattended-upgrades is a package that allows Ubuntu to automatically download and install security updates and other important updates without any user intervention. This can be useful for servers or other systems that are running 24/7, as it ensures that the system remains up-to-date with security patches and other important updates. Ubuntu 20.04 includes an automatic … Read more

On Linux, you can use the command line tool “date” to add days to a date and get a new date. Here’s an example of how you can add 30 days to the current date and get the new date: date –date=’30 days’ +%Y-%m-%d This command will add 30 days to the current date and … Read more

To save iptables firewall rules permanently on Linux, you can use the iptables-save and iptables-restore commands. Start by saving your current iptables rules by running the following command: sudo iptables-save > /etc/iptables/iptables.rules This command will save the current iptables rules to a file named “iptables.rules” in the “/etc/iptables” directory. To make sure that the iptables … Read more

On Linux systems using systemd, you can use the “systemctl” command to view the status of a service. The basic syntax for the command is: systemctl status [service_name] For example, to check the status of the Apache web server, you can use the command: systemctl status httpd This command will return the current status of … Read more

Awall is a firewall management tool for Alpine Linux that allows you to configure the firewall using a simple and easy to understand configuration file. Here’s how you can set up a firewall with Awall on Alpine Linux: First, install the Awall package by running the command “apk add awall” Next, create a configuration file … Read more

In Alpine Linux, you can change the hostname (computer name) by following these steps: First, open the system’s hostname configuration file, typically located at /etc/hostname, by running the following command: nano /etc/hostname Replace the current hostname with your desired hostname in the file, then save and close the file. Next, you should also update the … Read more

There are a few different ways to install Java on Ubuntu 20.04 LTS, but the most common way is to use the package manager. Here’s how you can do it: First, update your package lists by running the command “sudo apt update” Next, you can install the default OpenJDK package by running the command “sudo … Read more

ssh-agent is a program that allows you to store your private SSH keys in memory, so that you don’t have to enter the passphrase every time you use them. To use ssh-agent for authentication on Linux or Unix, you can follow these steps: Start by starting the ssh-agent program by running the following command: eval … Read more

You can create a Linux swap file by following these steps: First, check the available disk space by running the command “df -h”. This will show you the amount of free space available on your system. Decide on the size of the swap file. It’s recommended that the swap file size is at least twice … Read more