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28 .\" @(#)syslog.conf.5 8.1 (Berkeley) 6/9/93
42 file is the configuration file for the
46 blocks of lines separated by
50 specifications (separations appear along on the line),
51 with each line containing two fields: the
53 field which specifies the types of messages and priorities to which the
56 field which specifies the action to be taken if a message
58 receives matches the selection criteria.
61 field is separated from the
63 field by one or more tab characters or spaces.
65 Note that if you use spaces as separators, your
67 might be incompatible with other Unices or Unix-like systems.
68 This functionality was added for ease of configuration
69 (e.g.\& it is possible to cut-and-paste into
71 and to avoid possible mistakes.
72 This change however preserves
73 backwards compatibility with the old style of
75 (i.e., tab characters only).
83 an optional set of comparison flags
84 .Pq Oo \&! Oc Op <=> ,
87 with no intervening white-space.
96 describes the part of the system generating the message, and is one of
97 the following keywords: auth, authpriv, console, cron, daemon, ftp, kern,
98 lpr, mail, mark, news, ntp, security, syslog, user, uucp and local0 through
100 These keywords (with the exception of mark) correspond to
103 values specified to the
111 may be used to specify exactly what is logged.
112 The default comparison is
116 which means that messages from the specified
118 list, and of a priority
119 level equal to or greater than
122 Comparison flags beginning with
124 will have their logical sense inverted.
127 means all levels except info and
129 has the same meaning as
134 describes the severity of the message, and is a keyword from the
135 following ordered list (higher to lower): emerg, alert, crit, err,
136 warning, notice, info and debug.
137 These keywords correspond to
140 values specified to the
144 Each block of lines is separated from the previous block by a
149 A block will only log messages corresponding to the most recent
153 specifications given.
154 Thus, with a block which selects
158 directly followed by a block that selects messages from the
161 the second block will only log messages
168 specification is a line beginning with
172 (the former is for compatibility with the previous syslogd, if one is sharing
175 and the following blocks will be associated with calls to
177 from that specific program.
182 will also match any message logged by the kernel with the prefix
188 specification works just like the previous one,
193 specification will match any message but the ones from that
195 Multiple programs may be listed, separated by commas:
197 matches messages from either program, while
199 matches all messages but those from
206 specification of the form
210 means the following blocks will be applied to messages
211 received from the specified hostname.
218 causes the following blocks to be applied to messages
219 from any host but the one specified.
220 If the hostname is given as
222 the local hostname will be used.
223 As for program specifications, multiple comma-seprarated
224 values may be specified for hostname specifications.
230 specification may be reset by giving the program or hostname as
235 for further descriptions of both the
239 keywords and their significance.
240 It's preferred that selections be made on
244 since the latter can easily vary in a networked environment.
246 though, an appropriate
248 simply does not exist.
250 If a received message matches the specified
252 and is of the specified
254 .Em (or a higher level) ,
255 and the first word in the message after the date matches the
257 the action specified in the
263 may be specified for a single
265 by separating them with semicolon
268 It is important to note, however, that each
270 can modify the ones preceding it.
274 may be specified for a single
276 by separating them with comma
282 can be used to specify all
292 receives a message at priority
297 This is not enabled by a
299 field containing an asterisk.
304 disables a particular
309 field of each line specifies the action to be taken when the
311 field selects a message.
312 There are five forms:
315 A pathname (beginning with a leading slash).
316 Selected messages are appended to the file.
318 To ensure that kernel messages are written to disk promptly,
322 after writing messages from the kernel.
323 Other messages are not synced explicitly.
324 You may prefix a pathname with the minus sign,
326 to forego syncing the specified file after every kernel message.
327 Note that you might lose information if the system crashes
328 immediately following a write attempt.
329 Nevertheless, using the
331 option may improve performance,
332 especially if the kernel is logging many messages.
334 A hostname (preceded by an at
337 Selected messages are forwarded to the
339 program on the named host.
341 A comma separated list of users.
342 Selected messages are written to those users
343 if they are logged in.
346 Selected messages are written to all logged-in users.
350 followed by a command to pipe the selected
352 The command is passed to
354 for evaluation, so usual shell metacharacters or input/output
355 redirection can occur.
356 (Note however that redirecting
358 buffered output from the invoked command can cause additional delays,
359 or even lost output data in case a logging subprocess exited with a
361 The command itself runs with
370 will close the pipe to the process.
371 If the process did not exit
372 voluntarily, it will be sent a
374 signal after a grace period of up to 60 seconds.
376 The command will only be started once data arrives that should be piped
378 If it exited later, it will be restarted as necessary.
380 is desired that the subprocess should get exactly one line of input only
381 (which can be very resource-consuming if there are a lot of messages
382 flowing quickly), this can be achieved by exiting after just one line of
384 If necessary, a script wrapper can be written to this effect.
386 Unless the command is a full pipeline, it's probably useful to
387 start the command with
389 so that the invoking shell process does not wait for the command to
391 Warning: the process is started under the UID invoking
393 normally the superuser.
396 Blank lines and lines whose first non-blank character is a hash
398 character are ignored.
399 .Sh IMPLEMENTATION NOTES
402 facility is usually reserved for messages
403 generated by the local kernel.
404 Other messages logged with facility
406 are usually translated to facility
408 This translation can be disabled;
413 .Bl -tag -width /etc/syslog.conf -compact
414 .It Pa /etc/syslog.conf
419 A configuration file might appear as follows:
421 # Log all kernel messages, authentication messages of
422 # level notice or higher, and anything of level err or
423 # higher to the console.
424 # Don't log private authentication messages!
425 *.err;kern.*;auth.notice;authpriv.none /dev/console
427 # Log anything (except mail) of level info or higher.
428 # Don't log private authentication messages!
429 *.info;mail.none;authpriv.none /var/log/messages
431 # Log daemon messages at debug level only
432 daemon.=debug /var/log/daemon.debug
434 # The authpriv file has restricted access.
435 authpriv.* /var/log/secure
437 # Log all the mail messages in one place.
438 mail.* /var/log/maillog
440 # Everybody gets emergency messages, plus log them on another
443 *.emerg @arpa.berkeley.edu
445 # Root and Eric get alert and higher messages.
448 # Save mail and news errors of level err and higher in a
450 uucp,news.crit /var/log/spoolerr
452 # Pipe all authentication messages to a filter.
453 auth.* |exec /usr/local/sbin/authfilter
455 # Save ftpd transactions along with mail and news
457 *.* /var/log/spoolerr
459 # Log all security messages to a separate file.
460 security.* /var/log/security
462 # Log all writes to /dev/console to a separate file.
463 console.* /var/log/console.log
465 # Log ipfw messages without syncing after every message.
473 The effects of multiple
475 are sometimes not intuitive.
480 facility messages at the level of
482 or higher, not at the level of
486 In networked environments, note that not all operating systems
487 implement the same set of facilities.
489 authpriv, cron, ftp, and ntp that are known to this implementation
490 might be absent on the target system.
491 Even worse, DEC UNIX uses
492 facility number 10 (which is authpriv in this implementation) to
493 log events for their AdvFS file system.