I was always doing a commit before exiting SQL*Plus when it occurred to me today that maybe I didn’t need to do that.  Doing a Google search quickly answered that for me.

If you issue a graceful exit (via the “exit” or “quit” command), sqlplus will always issue a commit. However, if you were to be ungracefully disconnected, for example by closing your terminal window, then PMON will issue a rollback like it does with any other disconnected session.

sqlplus commit-on-exit?

Therefore there is no need to do a commit before you exit.

You can also set autocommit on, it is off by default, but I would not recommend doing this.

During interactive usage with sqlplus, Oracle also supports an AUTOCOMMIT option. With this option set to ON each individual SQL statement is treated as a transaction an will be automatically commited right after it is executed. A user can change the AUTOCOMMIT option by typing

 SET AUTOCOMMIT ON

or

 SET AUTOCOMMIT OFF

whereas by typing

 SHOW ALL

a user can see the current setting for the option (including other ones).

Oracle SQL Transactions