Berkeley syslogd (and kin) are configured via the file /etc/syslog.conf

Each loggable event has associated with it a facility and a severity level

The facility is typically one of: 

auth authpriv console cron

daemon ftp kern lpr

mail mark news ntp

security syslog user uucp  local0..local7

  The severity level is one of:

emerg alert

crit err

warning notice

info debug

Unfortunately, features, facility codes, and behavior are very different even among the BSDs

 

Some versions can pipe to programs, others only to named pipes

 

Some can show facility and severity level in logs; others can't

 

Some can route messages according to "tags;" some can't