How to upgrade Ubuntu 16.04 to 18.04 LTS using CLI

To upgrade Ubuntu 16.04 to 18.04 LTS using the command line, you can use the following steps:

1. Open a terminal and run the following command to update the package lists:

sudo apt update

2. Run the following command to upgrade all installed packages to the latest version:

sudo apt upgrade

3. Run the following command to install the update-manager-core package, which is required to perform the upgrade:

sudo apt install update-manager-core

4. Run the following command to start the upgrade process:

sudo do-release-upgrade

This will start the upgrade process to Ubuntu 18.04 LTS. Follow the prompts to complete the upgrade.

Note that upgrading to a newer version of Ubuntu can be a complex process and may require additional steps, depending on your system configuration. It's recommended to back up your data and consult the documentation for the new version of Ubuntu before upgrading.