Oracle: Handle error codes with sqlplus

Tom Kyte explains it here:
http://tkyte.blogspot.fr/2010/04/new-thing-about-sqlplus.html

1. Start with

   set errorlogging on identifier toto
   delete from sperrorlog where identifier = 'toto'
   /
   

2. Then use some sqlplus commands
3. And terminate with

   col nb_errors new_value nb_errors
   select count(*) as nb_errors from sperrorlog where identifier = 'toto'
   /
   exit nb_errors

This allows for testings the return code of sqlplus in a bash / perl script.

NB: See http://ss64.com/ora/syntax-sqlplus.html for the sqlplus syntax