freebsd-dev/usr.sbin/newsyslog/newsyslog.8

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.Dd April 27, 2003
.Dt NEWSYSLOG 8
.Os
.Sh NAME
.Nm newsyslog
.Nd maintain system log files to manageable sizes
.Sh SYNOPSIS
.Nm
.Op Fl CFnrsv
.Op Fl R Ar tagname
.Op Fl a Ar directory
.Op Fl f Ar config_file
.Op Ar
.Sh DESCRIPTION
The
.Nm
utility should be scheduled to run periodically by
.Xr cron 8 .
When it is executed it archives log files if necessary.  If a log file
is determined to require archiving,
.Nm
rearranges the files so that
.Dq Va logfile
is empty,
.Dq Va logfile Ns Li \&.0
has
the last period's logs in it,
.Dq Va logfile Ns Li \&.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.
.Pp
A log can be archived for three reasons:
.Bl -enum -offset indent
.It
It is larger than the configured size (in kilobytes).
.It
A configured number of hours have elapsed since the log was last
archived.
.It
This is the specific configured hour for rotation of the log.
.El
.Pp
The granularity of
.Nm
is dependent on how often it is scheduled to run by
.Xr 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.
.Pp
When starting up,
.Nm
reads in a configuration file to determine which logs may potentially
be archived.
By default, this configuration file is
.Pa /etc/newsyslog.conf .
Each line of the file contains information about a particular log file
that should be handled by
.Nm .
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:
.Pp
.Bl -tag -width indent
.It Ar logfile_name
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
.Nm
command, and if that log file name is not matched by any other
line in the configuration file.
.It Ar owner : Ns Ar group
This optional field specifies the owner and group for the archive file.
The ":" is essential, even if the
.Ar owner
or
.Ar group
field is left blank.  The field may be numeric, or a name which is
present in
.Pa /etc/passwd
or
.Pa /etc/group .
.It Ar mode
Specify the mode of the log file and archives.
.It Ar count
Specify the number of archive files to be kept
besides the log file itself.
.It Ar size
When the size of the log file reaches
.Ar size
in kilobytes,
the log file will be trimmed as described above.  If this field
is replaced by an asterisk
.Pq Ql \&* ,
then the size of the log file is not taken into account
when determining when to trim the log file.
.It Ar when
The
.Ar when
field can consist of an interval, a specific time, or both.  If
the
.Ar when
field is an asterisk
.Pq Ql \&*
log rotation will depend only on the contents of the
.Ar size
field.
Otherwise, the
.Ar when
field consists of an optional interval in hours, optionally followed
by an
.So Li \&@ Sc Ns No -sign
and a time in a restricted
.Tn ISO 8601
format or by an
.So Li \&$ Sc Ns No -sign
and a time specification for logfile rotation at a fixed time once
per day, per week or per month.
.Pp
If a time is specified, the log file will only be trimmed if
.Nm
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.
.Pp
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'.
.Pp
.Sy ISO 8601 restricted time format
.Pp
The lead-in character for a restricted
.Tn ISO 8601
time is
an
.So Li \&@ Sc Ns No -sign .
The particular format of the time in restricted
.Tn ISO 8601
is:
.Sm off
.Oo
.Oo
.Oo
.Oo
.Oo
.Va \&cc
.Oc
.Va \&yy
.Oc
.Va \&mm
.Oc
.Va \&dd
.Oc
.Oo
.Li \&T
.Oo
.Va \&hh
.Oo
.Va \&mm
.Oo
.Va \&ss
.Oc
.Oc
.Oc
.Oc
.Oc .
.Sm on
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:
.Pp
.Bl -item -compact -offset indent
.It
.Sq Li 19990122T000000
.It
.Sq Li 990122T000000
.It
.Sq Li 0122T000000
.It
.Sq Li 22T000000
.It
.Sq Li T000000
.It
.Sq Li T0000
.It
.Sq Li T00
.It
.Sq Li 22T
.It
.Sq Li \&T
.It
.Sq Li \&
.El
.Pp
.Sy Day, week and month time format
.Pp
The lead-in character for day, week and month specification is a
.So Li \&$ Sc Ns No -sign .
The particular format of day, week and month specification is:
.Op Va D\&hh ,
.Op Va W\&w Ns Op Va D\&hh
and
.Op Va M\&dd Ns Op Va D\&hh
respectively.
Optional time fields default to midnight.
The ranges for day and hour specifications are:
.Pp
.Bl -tag -width Ds -compact -offset indent
.It Ar hh
hours, range 0 ... 23
.It Ar w
day of week, range 0 ... 6, 0 = Sunday
.It Ar dd
day of month, range 1 ... 31, or the letter
.Em L
or
.Em l
to specify the last day of the month.
.El
.Pp
Some examples:
.Pp
.Bl -tag -width Ds -compact -offset indent
.It Ar $D0
rotate every night at midnight
(same as
.Ar @T00 )
.It Ar $D23
rotate every day at 23:00 hr
(same as
.Ar @T23 )
.It Ar $W0D23
rotate every week on Sunday at 23:00 hr
.It Ar $W5D16
rotate every week on Friday at 16:00 hr
.It Ar $M1D0
rotate at the first day of every month at midnight
(i.e., the start of the day; same as
.Ar @01T00 )
.It Ar $M5D6
rotate on every 5th day of month at 6:00 hr
(same as
.Ar @05T06 )
.El
.Pp
.It Ar 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:
.Bl -tag -width indent
.It Sy B
indicates that the log file is a binary file, or has some
special format.
Usually
.Nm
inserts an
.Tn ASCII
message into a log file when rotating the file, to indicate
when and sometimes why the log file was rotated.
If
.Sy B
is specified, then that informational message will not be
inserted into the log file.
.It Sy C
indicates that the log file should be created if it does not
already exist, and if the
.Fl C
option was also specified on the command line.
.It Sy G
indicates that the specified
.Ar logfile_name
is a shell pattern, and that
.Nm
should archive all filenames matching that pattern, using the
other options specified on this line.
See
.Xr glob 3
for details on syntax and matching rules.
.It Sy J
indicates that
.Nm
should attempt to save disk space by compressing the rotated
log file using
.Xr bzip2 1 .
.It Sy N
indicates that there is no process which needs to be signalled
when this log file is rotated.
.It Sy U
indicates that the file specified by
.Ar 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.
.It Sy W
if used with the
.Sy Z
or
.Sy J
flag, this indicates that
.Nm
should wait for previously started compression jobs to complete before
starting a new one for this entry.
If this is used with the
.Sy G
flag, and if multiple log files match the given pattern, then
.Nm
will compress those logs one by one.
This ensures that only one compression job is running at a time.
.It Sy Z
indicates that
.Nm
should attempt to save disk space by compressing the rotated
log file using
.Xr gzip 1 .
.It Sy -
a minus sign will not cause any special processing, but it
can be used as a placeholder to create a
.Ar flags
field when you need to specify any of the following fields.
.El
.It Ar path_to_pid_file
This optional field specifies the file name to read to find the daemon
process id, or to find a process group id if the
.Sy U
flag was specified.
If this field is present, a
.Ar 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
.Xr syslogd 8 ,
unless the
.Sy N
flag has been specified.
This field must start with "/" in order to be recognized
properly.
.It Ar signal_number
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
.Sy U
flag was specified).
If this field is not present, then a SIGHUP signal will be sent.
.El
.Sh OPTIONS
The following options can be used with
.Nm :
.Bl -tag -width indent
.It Fl f Ar config_file
Instruct
.Nm
to use
.Ar config_file
instead of
.Pa /etc/newsyslog.conf
for its configuration file.
.It Fl a Ar directory
Specify a
.Ar 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
.Ar directory .
If any component of the path
.Ar directory
does not exist,
it will be created when
.Nm
is run.
.It Fl v
Place
.Nm
in verbose mode.  In this mode it will print out each log and its
reasons for either trimming that log or skipping it.
.It Fl n
Cause
.Nm
not to trim the logs, but to print out what it would do if this option
were not specified.
.It Fl r
Remove the restriction that
.Nm
must be running as root.  Of course,
.Nm
will not be able to send a HUP signal to
.Xr syslogd 8
so this option should only be used in debugging.
.It Fl s
Specify that
.Nm
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
.Fl R
option, and in that case the compression will be done.
.It Fl C
If specified once, then
.Nm
will create any log files which do not exist, and which have the
.Sy C
flag specified in their config file entry.
If specified multiple times, then
.Nm
will create all log files which do not already exist.
If log files are given on the command-line, then the
.Fl C
or
.Fl CC
will only apply to those specific log files.
.It Fl F
Force
.Nm
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 problems.
.It Fl R Ar tagname
Specify that
.Nm
should rotate a given list of files, even if trim conditions are not
met for those files.
The
.Ar tagname
is only used in the messages written to the log files which are
rotated.
This differs from the
.Fl F
option in that one or more log files must also be specified, so that
.Nm
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
.Nm
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
.Nm
with the
.Fl R
option, it should make sure all of the log files are closed before
calling
.Nm ,
and then it should re-open the files after
.Nm
returns.
Usually the calling process will also want to specify the
.Fl s
option, so
.Nm
will not send a signal to the very process which called it to force
the rotate.
Skipping the signal step will also mean that
.Nm
will return faster, since
.Nm
normally waits a few seconds after any signal that is sent.
.El
.Pp
If additional command line arguments are given,
.Nm
will only examine log files that match those arguments; otherwise, it
will examine all files listed in the configuration file.
.Sh FILES
.Bl -tag -width /etc/newsyslog.confxxxx -compact
.It Pa /etc/newsyslog.conf
.Nm
configuration file
.El
.Sh BUGS
Doesn't yet automatically read the logs to find security breaches.
.Sh AUTHORS
.An Theodore Ts'o ,
MIT Project Athena
.Pp
Copyright 1987, Massachusetts Institute of Technology
.Sh COMPATIBILITY
Previous versions of the
.Nm
utility used the dot (``.'') character to
distinguish the group name.
Beginning with
.Fx 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.
.Sh "SEE ALSO"
.Xr gzip 1 ,
.Xr syslog 3 ,
.Xr chown 8 ,
.Xr syslogd 8