$ logger -t postfix -p mail.info 'Message from postfix'

$ cat cisco_log_gen.sh

while :
do
  logger -t cisco -p local0.info "Message 1"
  logger -t cisco -p local0.info "Message 2"
done

$ sh cisco_log_gen.sh

• How To Use Journalctl to View and Manipulate Systemd Logs

# journalctl -ra

# journalctl --no-pager

# journalctl -o json

# journalctl -o verbose

# journalctl -f

# journalctl -ra -u postfix

# journalctl -ra -p err

# man systemd.journal-fields

# journalctl SYSLOG_FACILITY=2

# man journald.conf

# journalctl --disk-usage

# journalctl --vacuum-size=1G

• Receiving Syslog messages with a systemd

• RSyslog — удобный способ сбора и обработки системных логов
• Настройка RSyslog на запись в базу данных MySQL

root@server:~# cat /etc/rsyslog.d/30-cisco.conf

local0.* -/var/log/cisco.log

root@server:~# touch /var/log/cisco.log

root@server:~# chown syslog:adm /var/log/cisco.log

root@server:~# restart rsyslog

root@server:~# tail -f /var/log/cisco.log

root@server:~# cat /etc/rsyslog.conf

...
$ModLoad imudp
$UDPServerRun 514
...

root@server:~# restart rsyslog

Использование почтовых псевдонимов

root@server:~# apt-get install logwatch

root@server:~# /etc/cron.daily/00logwatch

              0             kernel messages
              1             user-level messages
              2             mail system
              3             system daemons
              4             security/authorization messages
              5             messages generated internally by syslogd
              6             line printer subsystem
              7             network news subsystem
              8             UUCP subsystem
              9             clock daemon
             10             security/authorization messages
             11             FTP daemon
             12             NTP subsystem
             13             log audit
             14             log alert
             15             clock daemon (note 2)
             16             local use 0  (local0)
             17             local use 1  (local1)
             18             local use 2  (local2)
             19             local use 3  (local3)
             20             local use 4  (local4)
             21             local use 5  (local5)
             22             local use 6  (local6)
             23             local use 7  (local7)