Here is an example. Your directory path may vary.
foglight 2913 1 0 14:21 pts/0 00:00:00 /opt/foglight/postgresql/bin/postgres -D /opt/foglight/state/postgresql-data --port=15432
foglight 2914 2913 0 14:21 ? 00:00:00 postgres: logger process
foglight 2916 2913 0 14:21 ? 00:00:00 postgres: checkpointer process
foglight 2917 2913 0 14:21 ? 00:00:00 postgres: writer process
foglight 2918 2913 0 14:21 ? 00:00:00 postgres: wal writer process
foglight 2919 2913 0 14:21 ? 00:00:00 postgres: autovacuum launcher process
foglight 2920 2913 0 14:21 ? 00:00:00 postgres: stats collector process