$ psql -l
psql: could not connect to server: No existe el fichero ó directorio
        Is the server running locally and accepting
        connections on Unix domain socket "/var/run/postgresql/.s.PGSQL.5432"?


##Si mi salida de 

$ps -aux | grep postgres
postgres 18047  0.0  0.5   3688  1204 pts/1    S    00:45   0:00 su postgres
postgres 18049  0.0  0.9   4480  2112 pts/1    S+   00:45   0:00 bash
postgres 18186  0.0  1.0  18416  2396 ?        S    00:47   0:00 /usr/lib/postgresql/7.4/bin/postmaster -c unix_socket_directory=/var/run/postgresql -D /var/lib/postgresql/7.4/main
postgres 18189  0.0  0.4   9216   932 ?        S    00:47   0:00 postgres: stats buffer process 
postgres 18190  0.0  0.4   8356  1104 ?        S    00:47   0:00 postgres: stats collector process