SYSLOG.CONF(5) BSD File Formats Manual SYSLOG.CONF(5)
syslog.conf -- configuration file for syslogd(8)
The syslog.conf file is the configuration file for the syslogd(8) program. It consists of lines with two fields: the selector field which
specifies the types of messages and priorities to which the line applies, and an action field which specifies the action to be taken if a
message syslogd receives matches the selection criteria. The selector field is separated from the action field by one or more tab or space
characters. A rule can be splitted in several lines if all lines except the last are terminated with a backslash (``'').
The Selectors function are encoded as a facility, a period (``.''), and a level, with no intervening white-space. Both the facility and the
level are case insensitive.
The facility describes the part of the system generating the message, and is one of the following keywords: auth, authpriv, cron, daemon,
kern, lpr, mail, mark, news, syslog, user, uucp and local0 through local7. These keywords (with the exception of mark) correspond to the
similar ``LOG_'' values specified to the openlog(3) and syslog(3) library routines.
The level describes the severity of the message, and is a keyword from the following ordered list (higher to lower): emerg, alert, crit, err,
warning, notice and debug. These keywords correspond to the similar (LOG_) values specified to the syslog library routine.
See syslog(3) for a further descriptions of both the facility and level keywords and their significance.
If a received message matches the specified facility and is of the specified level (or a higher level), the action specified in the action
field will be taken.
Multiple selectors may be specified for a single action by separating them with semicolon (``;'') characters. It is important to note, how-
ever, that each selector can modify the ones preceding it.
Multiple facilities may be specified for a single level by separating them with comma (``,'') characters.
An asterisk (``*'') can be used to specify all facilities or all levels.
By default, a level applies to all messages with the same or higher level. The equal (``='') character can be prepended to a level to
restrict this line of the configuration file to messages with the very same level.
An exclamation mark (``!'') prepended to a level or the asterisk means that this line of the configuration file does not apply to the speci-
fied level (and higher ones). In conjunction with the equal sign, you can exclude single levels as well.
The special facility ``mark'' receives a message at priority ``info'' every 20 minutes (see syslogd(8)). This is not enabled by a facility
field containing an asterisk.
The special level ``none'' disables a particular facility.
The action field of each line specifies the action to be taken when the selector field selects a message. There are five forms:
o A pathname (beginning with a leading slash). Selected messages are appended to the file.
You may prepend a minus (``-'') to the path to omit syncing the file after each message log. This can cause data loss at system crashes,
but increases performance for programs which use logging extensively.
o A named pipe (fifo), beginning with a vertical bar (``|'') followed by a pathname. The pipe must be created with mkfifo(8) before syslogd
reads its configuration file. This feature is especially useful fo debugging.
o A hostname (preceded by an at (``@'') sign). Selected messages are forwarded to the syslogd program on the named host.
o A comma separated list of users. Selected messages are written to those users if they are logged in.
o An asterisk. Selected messages are written to all logged-in users.
Blank lines and lines whose first non-blank character is a hash (``#'') character are ignored.
A configuration file might appear as follows:
# Log all kernel messages, authentication messages of
# level notice or higher and anything of level err or
# higher to the console.
# Don't log private authentication messages!
# Log anything (except mail) of level info or higher.
# Don't log private authentication messages!
# The authpriv file has restricted access.
# Log all the mail messages in one place.
# Everybody gets emergency messages, plus log them on another
# Root and Eric get alert and higher messages.
# Save mail and news errors of level err and higher in a
# special file.
/etc/syslog.conf The syslogd(8) configuration file.
The effects of multiple selectors are sometimes not intuitive. For example ``mail.crit,*.err'' will select ``mail'' facility messages at the
level of ``err'' or higher, not at the level of ``crit'' or higher.
4.4BSD June 9, 1993 4.4BSD