Check database connectivity using Shell script

Use a script like this:

#!/bin/sh
echo "exit" | sqlplus -L uid/pwd@dbname | grep Connected > /dev/null
if [ $? -eq 0 ] 
then
   echo "OK"
else
   echo "NOT OK"
fi

echo "exit" assures that your program exits immediately (this gets piped to sqlplus). -L assures that sqlplus won't ask for password if credentials are not ok (which would make it get stuck as well).

(> /dev/null just hides output from grep, which we don't need because the results are accessed via $? in this case)

You can avoid the SQL prompt by doing:

sqlplus uid/pwd@database-schemaname < /dev/null

SqlPlus exits immediately.

Now just grep the output of the above as:

if sqlplus uid/pwd@database-schemaname < /dev/null | grep 'Connected to'; then
   # have connectivity to Oracle
else
   # No connectivity
fi