POSTGRESQL

sudo apt update -y
sudo apt install postgresql postgresql-contrib

Verificamos que este activa:

sudo systemctl status postgresql

To log in to your PostgreSQL instance, first switch to the postgres user. The Postgres user comes included by default with the installation of PostgreSQL. Then run the psql command as shown.

$ sudo -i -u postgres
$ psql
\q
exit

Chequear si la base de datos esta activa

sudo pg_isready

INSTALAR PGADMIN4

https://www.pgadmin.org/download/pgadmin-4-apt/

cat /etc/*release

Setup the repository

Install the public key for the repository (if not done previously):

sudo curl https://www.pgadmin.org/static/packages_pgadmin_org.pub | sudo apt-key add

Create the repository configuration file:

sudo sh -c 'echo "deb https://ftp.postgresql.org/pub/pgadmin/pgadmin4/apt/$(lsb_release -cs) pgadmin4 main" > /etc/apt/sources.list.d/pgadmin4.list && apt update'

En mi caso terndria que poner a mano el codename ya que para tricica no habia. O esditarlo luego en "Fuentes de Software":

sudo sh -c 'echo "deb https://ftp.postgresql.org/pub/pgadmin/pgadmin4/apt/bionic pgadmin4 main" > /etc/apt/sources.list.d/pgadmin4.list && apt update'

sudo apt update

Install pgAdmin

Install for both desktop and web modes:

sudo apt install pgadmin4

Install for desktop mode only: sudo apt install pgadmin4-desktop

Install for web mode only: sudo apt install pgadmin4-web

Configure the webserver, if you installed pgadmin4-web:

sudo /usr/pgadmin4/bin/setup-web.sh

CONTRASEÑA

La contraseña por defecto es postgres pero si necesitamos cambiarla:

sudo -i -u postgres
psql
alter user postgres with password '1234';
ALTER ROLE
\q
exit

SI NO FUNCIONA

Revisar el codename de nuestra distribucion con: lsb_release -cs
Si estamos en linux mint revisar el codename de Ubuntu con: cat /etc/*release

Si no podemos abrir el archivo vamos a inicio / "Fuentes de Software" / Repositorios adicionales / Añadir
y pegamos la direccion alli

"The repository 'http://apt.postgresql.org/pub/repos/apt tricia-pgdg Release' does not have a Release file., W:Updating from such a repository can't be done securely, and is therefore disabled by default., W:See apt-secure(8) manpage for repository creation and user configuration details., E:The repository 'https://ftp.postgresql.org/pub/pgadmin/pgadmin4/apt/tricia pgadmin4 Release' does not have a Release file."

si no instala el pgadmin4 verificar que este seleccionado, si nos marca error, probar cambiar el codename en el repo de tricica (linux Mint) a bionic (Ubuntu)

deb https://ftp.postgresql.org/pub/pgadmin/pgadmin4/apt/bionic pgadmin4 main