[root@yueqi ~]# su - highgo
Last login: Tue Feb 13 11:30:45 CST 2018 on pts/1
[highgo@yueqi ~]$ psql
psql (4.1.1)
Psql: Release 4.1.1
Connected to:
HighGo Database V4.1 Enterprise Edition Release 4.1.1 - 64-bit Production
Type "help" for help.
highgo=# show cluster_name ;
cluster_name 
--------------

(1 row)
highgo=# \q

$ psql -c 'SHOW cluster_name'
 cluster_name
--------------
 server1
(1 row)

$ ps aux|grep server1
postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: server1: writer process
...