usr.sbin/newsyslog/newsyslog.8

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.Dd January 31, 2011
.Dt NEWSYSLOG 8
.Os
.Sh NAME
.Nm newsyslog
.Nd maintain system log files to manageable sizes
.Sh SYNOPSIS
.Nm
.Op Fl CFNPnrsv
.Op Fl R Ar tagname
.Op Fl S Ar pidfile
.Op Fl a Ar directory
.Op Fl d Ar directory
.Op Fl f Ar config_file
.Op Fl t Ar timefmt
.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.
It is also possible to let archived log filenames be created using the
time the log file was archived instead of the sequential number using
the
.Fl t
option.
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.
.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 d Ar directory
Specify a
.Ar directory
which all log files will be relative to.
To allow archiving of logs outside the root, the
.Ar directory
passed to the
.Fl a
option is unaffected.
.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 t Ar timefmt
If specified
.Nm
will create the
.Dq rotated
logfiles using the specified time format instead of the default
sequential filenames.
The time format is described in the
.Xr strftime 3
manual page.
If the
.Ar timefmt
argument is set to an empty string or the string
.Dq DEFAULT ,
the default built in time format
is used.
If the
.Ar timefmt
string is changed the old files created using the previous time format
will not be be automatically removed (unless the new format is very
similar to the old format).
This is also the case when changing from sequential filenames to time
based file names, and the other way around.
The time format should contain at least year, month, day, and hour to
make sure rotating of old logfiles can select the correct logfiles.
.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 N
Do not perform any rotations.
This option is intended to be used with the
.Fl C
or
.Fl CC
options when creating log files is the only objective.
.It Fl P
Prevent further action if we should send signal but the
.Dq pidfile
is empty or does not exist.
.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.
.It Fl S Ar pidfile
Use
.Ar pidfile
as
.Xr syslogd 8 Ns 's
pidfile.
.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 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 bzip2 1 ,
.Xr gzip 1 ,
.Xr xz 1 ,
.Xr syslog 3 ,
.Xr newsyslog.conf 5 ,
.Xr chown 8 ,
.Xr syslogd 8
.Sh HISTORY
The
.Nm
utility originated from
.Nx
and first appeared in
.Fx 2.2 .
.Sh AUTHORS
.An Theodore Ts'o ,
MIT Project Athena
.Pp
Copyright 1987, Massachusetts Institute of Technology
.Sh BUGS
Does not yet automatically read the logs to find security breaches.