Команды - Sendmail, mail, mutt
sendmail user@example.com < /tmp/email.txt
mail -s "Test Email" user@example.com < /dev/null
mail -a /opt/backup.sql -s "Backup File" user@example.com < /dev/null
mail -s "Test Email" user@example.com,user2@example.com < /dev/null
mutt -s "backup" -a /var/spool/asterisk/backup/Default_backup/sql.tgz -- mail@mail.tld < /home/mail.txt