newsyslog -- maintain system log files to manageable sizes
newsyslog [-CFnrsv] [-R tagname] [-a directory] [-f config_file]
The newsyslog utility should be scheduled to run periodically by cron(8).
When it is executed it archives log files if necessary. If a log file is
determined to require archiving, newsyslog rearranges the files so that
``logfile'' is empty, ``logfile.0'' has the last period's logs in it,
``logfile.1'' has the next to last period's logs in it, and so on, up to
a user-specified number of archived logs. Optionally the archived logs
can be compressed to save space.
A log can be archived for three reasons:
1. It is larger than the configured size (in kilobytes).
2. A configured number of hours have elapsed since the log was
3. This is the specific configured hour for rotation of the log.
The granularity of newsyslog is dependent on how often it is scheduled to
run by cron(8). Since the program is quite fast, it may be scheduled to
run every hour without any ill effects, and mode three (above) assumes
that this is so.
When starting up, newsyslog reads in a configuration file to determine
which logs may potentially be archived. By default, this configuration
file is /etc/newsyslog.conf. Each line of the file contains information
about a particular log file that should be handled by newsyslog. Each
line has five mandatory fields and four optional fields, with whitespace
separating each field. Blank lines or lines beginning with ``#'' are
ignored. If ``#'' is placed in the middle of the line, ``#'' character
and the rest of the line after it is ignored. To prevent special meaning,
the ``#'' may be escaped with ``\'', in this case preceding ``\'' is
removed and ``#'' treated as ordinary character. The fields of the configuration
file are as follows:
Name of the system log file to be archived, or the literal string
``<default>''. The special default entry will be only be used if
some log file name is given as a command line argument on the
newsyslog command, and if that log file name is not matched by
any other line in the configuration file.
This optional field specifies the owner and group for the archive
file. The ":" is essential, even if the owner or group field is
left blank. The field may be numeric, or a name which is present
in /etc/passwd or /etc/group.
mode Specify the mode of the log file and archives.
count Specify the number of archive files to be kept besides the log
size When the size of the log file reaches size in kilobytes, the log
file will be trimmed as described above. If this field is
replaced by an asterisk (`*'), then the size of the log file is
not taken into account when determining when to trim the log
when The when field can consist of an interval, a specific time, or
both. If the when field is an asterisk (`*') log rotation will
depend only on the contents of the size field. Otherwise, the
when field consists of an optional interval in hours, optionally
followed by an `@'-sign and a time in a restricted ISO 8601 format
or by an `$'-sign and a time specification for logfile rotation
at a fixed time once per day, per week or per month.
If a time is specified, the log file will only be trimmed if
newsyslog is run within one hour of the specified time. If an
interval is specified, the log file will be trimmed if that many
hours have passed since the last rotation. When both a time and
an interval are specified, both conditions must be satisfied for
the rotation to take place.
There is no provision for specification of a timezone. There is
little point in specifying an explicit minutes or seconds component
in the current implementation, since the only comparison is
`within the hour'.
ISO 8601 restricted time format
The lead-in character for a restricted ISO 8601 time is an
`@'-sign. The particular format of the time in restricted ISO
8601 is: [[[[[cc]yy]mm]dd][T[hh[mm[ss]]]]]. Optional date fields
default to the appropriate component of the current date;
optional time fields default to midnight; hence if today is January
22, 1999, the following date specifications are all equivalent:
Day, week and month time format
The lead-in character for day, week and month specification is a
`$'-sign. The particular format of day, week and month specification
is: [Dhh], [Ww[Dhh]] and [Mdd[Dhh]] respectively.
Optional time fields default to midnight. The ranges for day and
hour specifications are:
hh hours, range 0 ... 23
w day of week, range 0 ... 6, 0 = Sunday
dd day of month, range 1 ... 31, or the letter L or l
to specify the last day of the month.
$D0 rotate every night at midnight (same as @T00)
$D23 rotate every day at 23:00 hr (same as @T23)
$W0D23 rotate every week on Sunday at 23:00 hr
$W5D16 rotate every week on Friday at 16:00 hr
$M1D0 rotate at the first day of every month at midnight
(i.e., the start of the day; same as @01T00)
$M5D6 rotate on every 5th day of month at 6:00 hr (same
flags This optional field is made up of one or more characters that
specify any special processing to be done for the log files
matched by this line. The following are valid flags:
B indicates that the log file is a binary file, or has some
special format. Usually newsyslog inserts an ASCII message
into a log file when rotating the file, to indicate
when and sometimes why the log file was rotated. If B is
specified, then that informational message will not be
inserted into the log file.
C indicates that the log file should be created if it does
not already exist, and if the -C option was also specified
on the command line.
G indicates that the specified logfile_name is a shell pattern,
and that newsyslog should archive all filenames
matching that pattern, using the other options specified
on this line. See glob(3) for details on syntax and
J indicates that newsyslog should attempt to save disk
space by compressing the rotated log file using bzip2(1).
N indicates that there is no process which needs to be signalled
when this log file is rotated.
U indicates that the file specified by path_to_pid_file
will contain the id for a process group, instead of a
process. This option also requires that the first line
in that file must be a negative value, to distinguish it
from a value for a process id.
W if used with the Z or J flag, this indicates that
newsyslog should wait for previously started compression
jobs to complete before starting a new one for this
entry. If this is used with the G flag, and if multiple
log files match the given pattern, then newsyslog will
compress those logs one by one. This ensures that only
one compression job is running at a time.
Z indicates that newsyslog should attempt to save disk
space by compressing the rotated log file using gzip(1).
- a minus sign will not cause any special processing, but
it can be used as a placeholder to create a flags field
when you need to specify any of the following fields.
This optional field specifies the file name to read to find the
daemon process id, or to find a process group id if the U flag
was specified. If this field is present, a signal_number is sent
the process id contained in this file. If this field is not
present, then a SIGHUP signal will be sent to syslogd(8), unless
the N flag has been specified. This field must start with "/" in
order to be recognized properly.
This optional field specifies the signal number that will be sent
to the daemon process (or to all processes in a process group, if
the U flag was specified). If this field is not present, then a
SIGHUP signal will be sent.
The following options can be used with newsyslog:
Instruct newsyslog to use config_file instead of
/etc/newsyslog.conf for its configuration file.
Specify a directory into which archived log files will be written.
If a relative path is given, it is appended to the path of
each log file and the resulting path is used as the directory
into which the archived log for that log file will be written.
If an absolute path is given, all archived logs are written into
the given directory. If any component of the path directory does
not exist, it will be created when newsyslog is run.
-v Place newsyslog in verbose mode. In this mode it will print out
each log and its reasons for either trimming that log or skipping
-n Cause newsyslog not to trim the logs, but to print out what it
would do if this option were not specified.
-r Remove the restriction that newsyslog must be running as root.
Of course, newsyslog will not be able to send a HUP signal to
syslogd(8) so this option should only be used in debugging.
-s Specify that newsyslog should not send any signals to any daemon
processes that it would normally signal when rotating a log file.
For any log file which is rotated, this option will usually also
mean the rotated log file will not be compressed if there is a
daemon which would have been signalled without this option. However,
this option is most likely to be useful when specified with
the -R option, and in that case the compression will be done.
-C If specified once, then newsyslog will create any log files which
do not exist, and which have the C flag specified in their config
file entry. If specified multiple times, then newsyslog will
create all log files which do not already exist. If log files
are given on the command-line, then the -C or -CC will only apply
to those specific log files.
-F Force newsyslog to trim the logs, even if the trim conditions
have not been met. This option is useful for diagnosing system
problems by providing you with fresh logs that contain only the
Specify that newsyslog should rotate a given list of files, even
if trim conditions are not met for those files. The tagname is
only used in the messages written to the log files which are
rotated. This differs from the -F option in that one or more log
files must also be specified, so that newsyslog will only operate
on those specific files. This option is mainly intended for the
daemons or programs which write some log files, and want to trigger
a rotate based on their own criteria. With this option they
can execute newsyslog to trigger the rotate when they want it to
happen, and still give the system administrator a way to specify
the rules of rotation (such as how many backup copies are kept,
and what kind of compression is done). When a daemon does execute
newsyslog with the -R option, it should make sure all of the
log files are closed before calling newsyslog, and then it should
re-open the files after newsyslog returns. Usually the calling
process will also want to specify the -s option, so newsyslog
will not send a signal to the very process which called it to
force the rotate. Skipping the signal step will also mean that
newsyslog will return faster, since newsyslog normally waits a
few seconds after any signal that is sent.
If additional command line arguments are given, newsyslog will only examine
log files that match those arguments; otherwise, it will examine all
files listed in the configuration file.
/etc/newsyslog.conf newsyslog configuration file
Doesn't yet automatically read the logs to find security breaches.
Theodore Ts'o, MIT Project Athena
Copyright 1987, Massachusetts Institute of Technology
Previous versions of the newsyslog utility used the dot (``.'') character
to distinguish the group name. Beginning with FreeBSD 3.3, this has been
changed to a colon (``:'') character so that user and group names may
contain the dot character. The dot (``.'') character is still accepted
for backwards compatibility.
gzip(1), syslog(3), chown(8), syslogd(8)
FreeBSD 5.2.1 April 27, 2003 FreeBSD 5.2.1 [ Back ]