Linux runs a “locally configured” mailer daemon that doesn't route messages by default through the Internet but only copies messages to other users spool directories
It is real SMTP-compliant email, it's just not routed over the Internet without configuration.
Locally email client send mail to other local users on the system by addressing to user@hostname, or by just specifying the user.
It can be found in the MAIL environment variable
This is called a spool file. Standard location are:
- or /var/spool/mail/USER
- mail (or Mail, mailx). Default
#centos yum install mailx
- less (to probe the file)
# shows the latest mails, at the end if the file less +G $MAIL less +G /var/spool/mail/root
The variable environment MAIL set the path of a mailbox