path: root/usr.bin/newsyslog/newsyslog.8

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.\"	from: @(#)newsyslog.8
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.\" Copyright 1988, 1989 by the Massachusetts Institute of Technology
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.\" used in advertising or publicity pertaining to distribution
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.Dd $Mdocdate: April 22 2024 $
.Dt NEWSYSLOG 8
.Os
.Sh NAME
.Nm newsyslog ,
.Nm newsyslog.conf
.Nd rotate log files
.Sh SYNOPSIS
.Nm newsyslog
.Op Fl Fmnrv
.Op Fl a Ar directory
.Op Fl f Ar config_file
.Op Ar log ...
.Sh DESCRIPTION
The
.Nm
utility rotates log files when they exceed a configurable size or age.
The
.Ar log
file is renamed to
.Pa log.0
and an empty file is created in its place.
An archive of older logs may be kept:
in order of increasing age, these files are named
.Pa log.1 ,
.Pa log.2 ,
and so on.
When their number exceeds a given limit, the oldest is removed.
The archived logs may also be compressed.
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl a Ar directory
Specify a
.Ar directory
into which archived log files will be written.
If
.Ar directory
is a relative path, it is appended to the parent directory
of each log and the archived log is stored in the result.
If an absolute path is given, all archived logs are stored in the given
.Ar directory .
If
.Ar directory
does not exist for a specified log, it is ignored for that entry and
the log is rotated as if the
.Fl a
option was not specified.
.It Fl F
Force
.Nm
to trim logs regardless of the size and/or age requirements specified in
.Pa /etc/newsyslog.conf .
This option may be combined with the
.Fl n
or
.Fl v
flags to aid in debugging problems with
.Pa /etc/newsyslog.conf .
.It Fl f Ar config_file
Use
.Ar config_file
instead of
.Pa /etc/newsyslog.conf
for the configuration file.
.It Fl m
Monitoring mode; only entries marked with an
.Sq M
in flags are processed.
For each log file being monitored, any log output since the last time
.Nm
was run with the
.Fl m
flag is mailed to the user listed in the monitor notification section.
.It Fl n
Do not trim the logs, but instead print out what would be done if this option
were not specified.
.It Fl r
Removes the restriction that
.Nm
must be running as root.
Note that in this mode
.Nm
will not be able to send a
.Dv SIGHUP
signal to
.Xr syslogd 8 .
.It Fl v
Place
.Nm newsyslog
in verbose mode.
In this mode it will print out each log and its
reasons for either trimming that log or skipping it.
.El
.Pp
In the default system configuration,
.Nm
is run by
.Xr cron 8 ,
but it may also be run manually.
If one or more
.Ar log
files are specified on the command line, only the specified files are
rotated.
Note that each
.Ar log
specified must have an entry in
.Pa /etc/newsyslog.conf .
.Pp
A log can be archived because of two reasons:
The log file can have
grown bigger than a preset size in kilobytes, or a preset number of
hours may have elapsed since the last log archive.
The granularity of
.Nm
is dependent on how often it is scheduled to run in
.Xr cron 8 .
Since the program is quite fast, it may be scheduled to run every hour
without any ill effects.
.Pp
When starting up,
.Nm
reads in a configuration file to determine which logs should be looked
at.
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 newsyslog .
Each line has five mandatory fields and up to three optional fields, with
whitespace separating each field.
Blank lines or lines beginning with a hash mark
.Pq Ql #
are ignored.
The fields of the configuration file are as
follows:
.Bl -tag -width XXXXXXXXXXXXXXXX
.It Ar logfile_name
The full pathname of the system log file to be archived.
.It Ar owner: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 fields may be numeric, or a name which is looked up
in the system password and group databases.
For backwards compatibility, a
.Ql \&.
may be used instead of a
.Ql \&: .
If either
.Ar owner
or
.Ar group
is not specified, the owner and/or group of the existing log file is used.
.It Ar mode
File mode (in octal) to use for created log files and archives.
.It Ar count
The number of archives to be kept besides the log file itself.
.It Ar size
When the size of the log file (in kilobytes) reaches this point, the log
file is trimmed as described above.
If this field is replaced by an
.Ql * ,
or set to
.Ql 0 ,
then the size of
the log file is not taken into account when determining when to trim the
log file.
By default, files smaller than 256 bytes are not rotated unless the
.Sq B
(binary) flag is set or the
.Fl F
option is specified.
This prevents
.Nm
from rotating files consisting solely of a message indicating
that the log file has been turned over.
.It Ar when
The
.Ar when
field can consist of an interval, a specific time, or both.
If the
.Ar when
field consists of 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, possibly followed
by an
.So Li \&@ Sc Ns -sign
and a time in a restricted
.St -iso8601
format or by a
.So Li \&$ Sc Ns -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 the specification of a time zone.
There is little point in specifying an explicit minutes or seconds
component in the current implementation, since the only comparison is
.Sq within the hour .
.Pp
.Sy ISO 8601 restricted time format:
The lead-in character for a restricted
.St -iso8601
time is an
.So Li \&@ Sc Ns -sign .
The particular format of the time in restricted
.St -iso8601
is:
.Sm off
.Oo Oo Oo Oo Oo
.Va \&cc Oc
.Va \&yy Oc
.Va \&mm Oc
.Va \&dd Oc
.Oo Va \&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.
For example, if today is January 22, 1999, the following date specifications
are all equivalent:
.Pp
.Bl -item -compact -offset indent
.It
.Ql 19990122T000000
.It
.Ql 990122T000000
.It
.Ql 0122T000000
.It
.Ql 22T000000
.It
.Ql T000000
.It
.Ql T0000
.It
.Ql T00
.It
.Ql 22T
.It
.Ql \&T
.It
.Ql \&
.El
.Pp
.Sy Day, week and month time format:
The lead-in character for day, week and month specification is a
dollar sign
.Pq $ .
The particular format of day, week and month specification is:
.Op Li D Ns Ar HH ,
.Op Li W Ns Ar w Ns Op Li D Ns Ar HH ,
and
.Op Li M Ns Ar dd Ns Op Li D Ns Ar 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
.Sy Some examples:
.Bl -tag -width Ds -compact -offset indent
.It Li $D0
rotate every night at midnight
(same as
.Li @T00 )
.It Li $D23
rotate every day at 23:00 hr
(same as
.Li @T23 )
.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 $M1D0
rotate on the first day of every month at midnight
(i.e., the start of the day; same as
.Li @01T00 )
.It Li $M5D6
rotate on every 5th day of the month at 6:00 hr
(same as
.Li @05T06 )
.El
.It Ar flags
The optional
.Ar flags
field specifies if the archives should have any special processing
done to the archived log files.
The
.Sq Z
flag will make the archive
files compressed to save space using
.Xr gzip 1
or
.Xr compress 1 ,
depending on compilation options.
The
.Sq B
flag means that the file is a
binary file, and so the ASCII message which
.Nm
inserts to indicate the fact that the logs have been turned over
should not be included.
The
.Sq M
flag marks this entry as a monitored
log file.
The
.Sq F
flag specifies that symbolic links should be followed.
.It Ar monitor
Specify the username (or email address) that should receive notification
messages if this is a monitored log file.
Notification messages are sent as email; the operator
deserves what they get if they mark the mail
log file as monitored.
This field is only valid when the
.Sq M
flag is set.
.It Ar pid_file
This optional field specifies a file containing the PID of a process to send a
signal (usually
.Dv SIGHUP )
to instead of
.Pa /var/run/syslog.pid .
.It Ar signal
This optional field specifies the signal to send to the process instead of
.Dv SIGHUP .
Signal names
must start with
.Dq SIG
and be the signal name, not the number, e.g.,
.Dv SIGUSR1 .
.It Ar command
This optional field specifies a command to run instead of sending a signal
to the process.
The command must be enclosed in double quotes
.Pq Ql \&" .
The empty string,
.Ql \&"\&" ,
can be used to prevent
.Nm
from sending a signal or running a command.
You cannot specify both a command and a PID file.
.Em NOTE:
If you specify a command to be run,
.Nm
will not send a
.Dv SIGHUP to
.Xr syslogd 8 .
.El
.Sh FILES
.Bl -tag -width /etc/newsyslog.conf
.It Pa /etc/newsyslog.conf
default configuration file
.El
.Sh EXIT STATUS
.Ex -std
.Sh SEE ALSO
.Xr compress 1 ,
.Xr gzip 1 ,
.Xr syslog 3 ,
.Xr syslogd 8
.Sh AUTHORS
.An Theodore Ts'o ,
MIT Project Athena
.br
Copyright 1987, Massachusetts Institute of Technology