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SYSLOG.CONF(5)		    BSD	File Formats Manual		SYSLOG.CONF(5)

     syslog.conf -- syslogd(8) configuration file

     The syslog.conf file is the configuration file for	the syslogd(8) pro-
     gram.  It consists	of blocks of lines separated by	program	and hostname
     specifications (separations appear	along on the line), with each line
     containing	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(8) receives
     matches the selection criteria.  The selector field is separated from the
     action field by one or more tab characters	or spaces.

     Note that if you use spaces as separators,	your syslog.conf might be in-
     compatible	with other Unices or Unix-like systems.	 This functionality
     was added for ease	of configuration (e.g. it is possible to cut-and-paste
     into syslog.conf),	and to avoid possible mistakes.	 This change however
     preserves backwards compatibility with the	old style of syslog.conf
     (i.e., tab	characters only).

     The selectors are encoded as a facility, a	period ("."), an optional set
     of	comparison flags ([!] [<=>]), 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, console,	cron, daemon,
     ftp, kern,	lpr, mail, mark, news, ntp, security, syslog, user, uucp and
     local0 through local7.  These keywords (with the exception	of mark) cor-
     respond to	similar	"LOG_" values specified	to the openlog(3) and
     syslog(3) library routines.

     The comparison flags may be used to specify exactly what is logged.  The
     default comparison	is "=>"	(or, if	you prefer, ">="), which means that
     messages from the specified facility list,	and of a priority level	equal
     to	or greater than	level will be logged.  Comparison flags	beginning with
     "!" will have their logical sense inverted.  Thus "!=info"	means all lev-
     els except	info and "!notice" has the same	meaning	as "<notice".

     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, info and debug.  These keywords correspond to similar
     "LOG_" values specified to	the syslog(3) library routine.

     Each block	of lines is separated from the previous	block by a program or
     hostname specification.  A	block will only	log messages corresponding to
     the most recent program and hostname specifications given.	 Thus, with a
     block which selects `ppp' as the program, directly	followed by a block
     that selects messages from	the hostname `dialhost', the second block will
     only log messages from the	ppp(8) program on dialhost.

     A program specification is	a line beginning with `#!prog' or `!prog' (the
     former is for compatibility with the previous syslogd, if one is sharing
     syslog.conf files,	for example) and the following blocks will be associ-
     ated with calls to	syslog(3) from that specific program.  A program spec-
     ification for `foo' will also match any message logged by the kernel with
     the prefix	`foo: '.  The `#!+prog'	or `!+prog' specification works	just
     like the previous one, and	the `#!-prog' or `!-prog' specification	will
     match any message but the ones from that program.	Multiple programs may
     be	listed,	separated by commas: `!prog1,prog2' matches messages from ei-
     ther program, while `!-prog1,prog2' matches all messages but those	from
     `prog1' or	`prog2'.

     A hostname	specification of the form `#+hostname' or `+hostname' means
     the following blocks will be applied to messages received from the	speci-
     fied hostname.  Alternatively, the	hostname specification `#-hostname' or
     `-hostname' causes	the following blocks to	be applied to messages from
     any host but the one specified.  If the hostname is given as `@', the lo-
     cal hostname will be used.	 As for	program	specifications,	multiple
     comma-seprarated values may be specified for hostname specifications.

     A program or hostname specification may be	reset by giving	the program or
     hostname as `*'.

     See syslog(3) for further descriptions of both the	facility and level
     keywords and their	significance.  It's preferred that selections be made
     on	facility rather	than program, since the	latter can easily vary in a
     networked environment.  In	some cases, though, an appropriate facility
     simply doesn't exist.

     If	a received message matches the specified facility and is of the	speci-
     fied level	(or a higher level), and the first word	in the message after
     the date matches the program, 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, however,
     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, all levels, or
     all programs.

     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.

	 To ensure that	kernel messages	are written to disk promptly,
	 syslog.conf calls fsync(2) after writing messages from	the kernel.
	 Other messages	are not	synced explicitly.  You	may prefix a pathname
	 with the minus	sign, "-", to forego syncing the specified file	after
	 every kernel message.	Note that you might lose information if	the
	 system	crashes	immediately following a	write attempt.	Nevertheless,
	 using the "-" option may improve performance, especially if the ker-
	 nel is	logging	many messages.

     o	 A hostname (preceded by an at ("@") sign).  Selected messages are
	 forwarded to the syslogd(8) 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.

     o	 A vertical bar	("|"), followed	by a command to	pipe the selected mes-
	 sages to.  The	command	is passed to sh(1) for evaluation, so usual
	 shell metacharacters or input/output redirection can occur.  (Note
	 however that redirecting stdio(3) buffered output from	the invoked
	 command can cause additional delays, or even lost output data in case
	 a logging subprocess exited with a signal.)  The command itself runs
	 with stdout and stderr	redirected to /dev/null.  Upon receipt of a
	 SIGHUP, syslogd(8) will close the pipe	to the process.	 If the
	 process didn't	exit voluntarily, it will be sent a SIGTERM signal af-
	 ter a grace period of up to 60	seconds.

	 The command will only be started once data arrives that should	be
	 piped to it.  If it exited later, it will be restarted	as necessary.
	 So if it is desired that the subprocess should	get exactly one	line
	 of input only (which can be very resource-consuming if	there are a
	 lot of	messages flowing quickly), this	can be achieved	by exiting af-
	 ter just one line of input.  If necessary, a script wrapper can be
	 written to this effect.

	 Unless	the command is a full pipeline,	it's probably useful to	start
	 the command with exec so that the invoking shell process does not
	 wait for the command to complete.  Warning: the process is started
	 under the UID invoking	syslogd(8), normally the superuser.

     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!
     *.err;kern.*;auth.notice;authpriv.none  /dev/console

     # Log anything (except mail) of level info	or higher.
     # Don't log private authentication	messages!
     *.info;mail.none;authpriv.none	     /var/log/messages

     # Log daemon messages at debug level only
     daemon.=debug					     /var/log/daemon.debug

     # The authpriv file has restricted	access.
     authpriv.*						     /var/log/secure

     # Log all the mail	messages in one	place.
     mail.*						     /var/log/maillog

     # Everybody gets emergency	messages, plus log them	on another
     # machine.
     *.emerg						     *

     # Root and	Eric get alert and higher messages.
     *.alert						     root,eric

     # Save mail and news errors of level err and higher in a
     # special file.
     uucp,news.crit					     /var/log/spoolerr

     # Pipe all	authentication messages	to a filter.
     auth.*				     |exec /usr/local/sbin/authfilter

     # Save ftpd transactions along with mail and news
     *.*						     /var/log/spoolerr

     # Log all security	messages to a separate file.
     security.*						     /var/log/security

     # Log all writes to /dev/console to a separate file.
     console.*						     /var/log/console.log

     # Log ipfw	messages without syncing after every message.
     *.*						     -/var/log/ipfw

     The "kern"	facility is usually reserved for messages generated by the lo-
     cal kernel.  Other	messages logged	with facility "kern" are usually
     translated	to facility "user".  This translation can be disabled; see
     syslogd(8)	for details.

     /etc/syslog.conf  syslogd(8) configuration	file

     The effects of multiple selectors are sometimes not intuitive.  For exam-
     ple "mail.crit,*.err" will	select "mail" facility messages	at the level
     of	"err" or higher, not at	the level of "crit" or higher.

     In	networked environments,	note that not all operating systems implement
     the same set of facilities.  The facilities authpriv, cron, ftp, and ntp
     that are known to this implementation might be absent on the target sys-
     tem.  Even	worse, DEC UNIX	uses facility number 10	(which is authpriv in
     this implementation) to log events	for their AdvFS	file system.

     syslog(3),	syslogd(8)

BSD				 June 9, 1993				   BSD


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