[postgres@node2 data]$ psql
psql: could not connect to server: No such file or directory
 Is the server running locally and accepting
 connections on Unix domain socket "/tmp/.s.PGSQL.5432

[postgres@node2 data]$ psql -p 5435
psql (9.6.1)
Type "help" for help.
postgres=# 

export PGPORT=5435

[postgres@node2 ~]$ source ~/.bash_profile 
[postgres@node2 ~]$ psql
psql (9.6.1)
Type "help" for help.
postgres=# 

[stork@instance-609xznso pgsql]$ /usr/pgsql-11/bin/psql c3_data -p 5432
could not change directory to “/var/lib/pgsql”: Permission denied
Password for user stork:
psql (11.5)
Type “help” for help.
c3_data=>

/usr/pgsql-11/bin/psql xxdatabase -p 端口号