• 方式1：登录，再切换到jetlinks数据库

$ sudo -u postgres psql

postgres=# \c jetlinks;
You are now connected to database "jetlinks" as user "postgres".
jetlinks=# 

• 方式2：直接登录到数据库

$ sudo -u postgres psql jetlinks

•  查看当前情况

jetlinks=# \conninfo
You are connected to database "jetlinks" as user "postgres" via socket in "/var/run/postgresql" at port "5432".