.\"	$NetBSD: newsyslog.8,v 1.46 2021/03/02 10:17:25 uwe Exp $
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.\" Copyright (c) 1999, 2000 Andrew Doran <ad@NetBSD.org>
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.\" This file contains changes from the Open Software Foundation.
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.\" from FreeBSD: newsyslog.8,v 1.14.2.1 1999/02/25 18:38:33 wollman Exp
.\"
.Dd March 1, 2021
.Dt NEWSYSLOG 8
.Os
.Sh NAME
.Nm newsyslog ,
.Nm newsyslog.conf
.Nd maintain system log files to manageable sizes
.Sh SYNOPSIS
.Nm newsyslog
.Op Fl Fnrsv
.Op Fl f Ar config_file
.Op Pa file ...
.Sh DESCRIPTION
.Nm
is a program that 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
The configured time for rotation of the log occurred within the last 60
minutes.
.El
.Pp
The granularity of
.Nm
is dependent on how often it is scheduled to run by
.Xr cron 8 .
It is recommended that
.Nm
be run once hourly.
.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 six mandatory fields and three optional fields, with
whitespace separating each field.
Blank lines or lines beginning with
.Ql #
are ignored.
The fields of the configuration file are as
follows:
.Bl -tag -width Fl
.It Ar logfile_name
Name of the system log file to be archived.
.It Ar owner Ns Li \&: Ns Ar group
This optional field specifies the owner and group for the archive file.
The
.Ql \&:
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 .
For backward compatibility,
.Ql \&.
is usable in lieu of
.Ql \&: ,
however use of this feature is discouraged.
.It Ar mode
Specify the mode of the log file and archives.
.It Ar ngen
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
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 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, the log will be trimmed if either condition is met.
.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
.Em ISO 8601 restricted time format
.Pp
The lead-in character for a restricted ISO 8601 time is an
.So Li \&@ Sc Ns No -sign .
The particular format of the time in restricted 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
.Em 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:
.Oo
.Li D Ns Va \&hh
.Oc ,
.Sm off
.Oo
.Li W Ns Va \&w
.Oo
.Li D Ns Va \&hh
.Oc
.Oc
.Sm on
and
.Sm off
.Oo
.Li M Ns Va \&dd
.Oo
.Li D Ns Va \&hh
.Oc
.Oc
.Sm on
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
.Ql L
or
.Ql l
to specify the last day of the month.
.El
.Pp
Some examples:
.Pp
.Bl -tag -width Ds -compact -offset indent
.It Li $D0
rotate every night at midnight
.It Li $D23
rotate every day at 23:00 hr
.It Li $W0D23
rotate every week on Sunday at 23:00 hr
.It Li $W5D16
rotate every week on Friday at 16:00 hr
.It Li $MLD0
rotate at the last day of every month at midnight
.It Li $M5D6
rotate on every 5th day of month at 6:00 hr
.El
.It Ar flags
This field specifies any special processing that is required.
These flags are parsed in a case insensitive manner.
Individual
flags and their meanings:
.Bl -tag -width indent
.It Ic \-
This flag means nothing \(em it is used as a spacer when no flags are set.
.It Ic b
The file is a binary file or is not in
.Xr syslogd 8
format: the ASCII message which
.Nm
inserts to indicate that the logs have been trimmed should not be included.
.It Ic c
Create an empty log file if none currently exists.
.It Ic e
Do not rotate log file with zero size (empty).
This flag is mostly usable in conjunction with
.Ic b
flag that prevents
.Nm
from inserting an ASCII informational message.
.It Ic j
Archived log files should be compressed with
.Xr bzip2 1
to save space.
.It Ic n
No signal should be sent when the log is trimmed.
.It Ic p
The first historical log file (i.e. the historical log file with the suffix
.Ql \.0 )
should not be compressed.
.It Ic x
Archived log files should be compressed with
.Xr xz 1
to save space.
.It Ic z
Archived log files should be compressed with
.Xr gzip 1
to save space.
.El
.It Ar path_to_pid_file
This optional field specifies
the file name to read to find the daemon process id.
If this field is missing, it defaults to the
.Pa /var/run/syslogd.pid
file.
A signal of type
.Ar sigtype
is sent to the process id contained in this
.Ar path_to_pid_file
file.
This field must start with
.Ql /
in order to be recognized properly.
.It Ar sigtype
This optional field specifies the type of signal to be sent to the daemon
process.
This may be a numeric or symbolic value.
By default a
.Dv SIGHUP
(hang-up) will be sent.
.El
.Sh OPTIONS
The following options can be used with newsyslog:
.Bl -tag -width indent
.It Fl F
Force trimming of 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.
.It Fl f Ar config_file
Use
.Ar config_file
instead of
.Pa /etc/newsyslog.conf
as the configuration file.
.It Fl n
Do not trim the logs, but print out what would be done if this option were not
specified:
.Fl n
implies
.Fl v .
.It Fl r
Remove the restriction that
.Nm
must be running as root.
When running as a regular user,
.Nm
will not be able to send a
.Dv SIGHUP
signal to
.Xr syslogd 8 ,
so this option should be used only when debugging or trimming user generated
logs.
.It Fl s
Do not signal daemon processes.
.It Fl v
Run in verbose mode.
In this mode each action that is taken will be printed.
.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 SEE ALSO
.Xr bzip2 1 ,
.Xr gzip 1 ,
.Xr syslog 3 ,
.Xr syslogd 8