Remove old postgres

sudo apt remove --purge postgresql\* -y

Remove binary if exist

sudo rm -f /usr/bin/psql
sudo rm -f /usr/share/postgresql-common
sudo rm -rf /usr/lib/postgresql

Clear dependencies if exist

sudo apt autoremove -y
sudo apt autoclean

which psql

which psql

This should return not found

Install new postgres

sudo apt update
sudo apt install postgresql postgresql-contrib libpq-dev
sudo service postgresql start

psql --version

Set new user and role

sudo -u postgres createuser -s xyborg -P

login as xyborg

psql -U xyborg -d postgres

create db

create database lilo

connect db

\c lilo