Identity

Unit: postgresql@16-main.service (Debian/Ubuntu), postgresql-16.service (RHEL/Fedora)
Config (Debian): /etc/postgresql/16/main/postgresql.conf, /etc/postgresql/16/main/pg_hba.conf
Config (RHEL): /var/lib/pgsql/16/data/postgresql.conf, /var/lib/pgsql/16/data/pg_hba.conf
Data dir (Debian): /var/lib/postgresql/16/main/
Data dir (RHEL): /var/lib/pgsql/16/data/
Logs (Debian): /var/log/postgresql/postgresql-16-main.log
Logs (RHEL): journalctl -u postgresql-16, or $PGDATA/log/ if logging_collector=on
Postgres superuser: postgres (OS user and DB superuser — separate concepts)
Install (Debian): apt install postgresql-16
Install (RHEL): dnf install postgresql16-server && postgresql-16-setup initdb

Key Operations

Operation	Command
Service status	`systemctl status postgresql@16-main` (Debian) / `systemctl status postgresql-16` (RHEL)
Reload config	`sudo systemctl reload postgresql@16-main` or `SELECT pg_reload_conf();` in psql
Connect as postgres	`sudo -u postgres psql`