TSNPING

TNSPING is a utility used to test if a SQL*Net connect string can connect to a remote listener. TnsPing only tests if the listener is available. It cannot tell if the databases behind the listener is up or not.

Syntax:
      TNSPING TnsName

Key
   TnsName  The TNS name for the remote database.
            This may (but does not have to) match the dbname.

Install location : ORACLE HOME/bin

“Make everything as simple as possible, but not simpler” ~ Albert Einstein

Related:

Oracle error ORA-12154 - TNS:could not resolve service name.
Oracle Networking - TNSNames, Listener.ora