This applies to CentOS 6. You may want to do this when testing some code and you’re not sure if it is going to send emails or not.
Add following lines at the bottom:
myhostname = localhost mydomain = localdomain inet_interfaces = $myhostname, localhost mydestination = $myhostname, localhost.$mydomain, localhost mynetworks_style = host default_transport = error:outside mail is not deliverable
Save the file then run the following commands (as root)
postfix upgrade-configuration postfix check newaliases
Test by mailing something to yourself
Check that it just gets put in the root mailbox
Enter the number of the email you want to read and it appears, d to delete it, z to return to the list, q to quit.