Summary: in this tutorial, you will learn step-by-step how to uninstall PostgreSQL from Ubuntu.

Here are the steps for uninstalling the PostgreSQL on Ubuntu:

• Uninstall the PostgreSQL application
• Remove PostgreSQL packages
• Remove PostgreSQL directories
• Delete the postgres user
• Verify uninstallation

The following is a step-by-step tutorial to uninstall PostgreSQL from Ubuntu:

Open the SSH terminal and run the following command to remove PostgreSQL from Ubuntu:

sudo apt-get --purge remove postgresql

Run the following command to show all installed PostgreSQL packages:

dpkg -l | grep postgres

The command will return a list of installed PostgreSQL packages.

To uninstall PostgreSQL completely, you need to remove all of these packages using the following command:

sudo apt-get --purge remove <package_name>

Replace <package_name> with the names of the installed packages.

Typically, you may have several packages such as postgresql, and postgresql-client-16. Make sure to remove all of them.

Remove the PostgreSQL’s related directories by executing the following commands:

sudo rm -rf /var/lib/postgresql/
sudo rm -rf /var/log/postgresql/
sudo rm -rf /etc/postgresql/

Typically, the PostgreSQL installer creates a system user postgres during the installation. To remove it, you can run the following command:

sudo deluser postgres

Finally, you can verify the uninstallation of PostgreSQL by using the following command:

psql --version

If PostgreSQL is uninstalled successfully, this command should return the following message:

-bash: /usr/bin/psql: No such file or directory

That’s it! PostgreSQL should now be completely uninstalled from your Ubuntu system.