Place code below in pgadmin4 directory, set each file permission to executable, and you can use it.
start.sh
#!/bin/sh
sudo systemctl start postgresql
sudo systemctl enable postgresql
systemctl status postgresql
python3 -m venv pgadmin4
source bin/activate
pgadmin4
stop.sh
#!/bin/sh
sudo systemctl stop postgresql
sudo systemctl disable postgresql
systemctl status postgresql
Nb: If you don't have postgresql and pgadmin4, you can follow the instruction from this page (for manjaro user)