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NEWSYSLOG(8)              BSD System Manager's Manual             NEWSYSLOG(8)

     newsyslog -- rotate log files

     newsyslog [-Fmnrv] [-a directory] [-f config_file] [log ...]

     The newsyslog utility rotates log files when they exceed a configurable
     size or age.  The log file is renamed to log.0 and an empty file is cre-
     ated in its place.  An archive of older logs may be kept: in order of
     increasing age, these files are named log.1, log.2, and so on.  When
     their number exceeds a given limit, the oldest is removed.  The archived
     logs may also be compressed.

     The options are as follows:

     -a directory
             Specify a directory into which archived log files will be writ-
             ten.  If directory is a relative path, it is appended to the par-
             ent 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 directory.  If directory does not exist for a
             specified log, it is ignored for that entry and the log is
             rotated as if the -a option was not specified.

     -F      Force newsyslog to trim logs regardless of the size and/or age
             requirements specified in /etc/newsyslog.conf.  This option may
             be combined with the -n or -v flags to aid in debugging problems
             with /etc/newsyslog.conf.

     -f config_file
             Use config_file instead of /etc/newsyslog.conf for the configura-
             tion file.

     -m      Monitoring mode; only entries marked with an 'M' in flags are
             processed.  For each log file being monitored, any log output
             since the last time newsyslog was run with the -m flag is mailed
             to the user listed in the monitor notification section.

     -n      Do not trim the logs, but instead print out what would be done if
             this option were not specified.

     -r      Removes the restriction that newsyslog must be running as root.
             Note that in this mode newsyslog will not be able to send a
             SIGHUP signal to syslogd(8).

     -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

     In the default system configuration, newsyslog is run by cron(8), but it
     may also be run manually.  If one or more log files are specified on the
     command line, only the specified files are rotated.  Note that each log
     specified must have an entry in /etc/newsyslog.conf.

     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 newsyslog is
     dependent on how often it is scheduled to run in cron(8).  Since the pro-
     gram is quite fast, it may be scheduled to run every hour without any ill

     When starting up, newsyslog reads in a configuration file to determine
     which logs should be looked at.  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 up to three optional fields, with whitespace
     separating each field.  Blank lines or lines beginning with a hash mark
     ('#') are ignored.  The fields of the configuration file are as follows:

     logfile_name      The full pathname of the system log file to be

     owner:group       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 fields may be
                       numeric, or a name which is looked up in the system
                       password and group databases.  For backwards compati-
                       bility, a '.' may be used instead of a ':'.  If either
                       owner or group is not specified, the owner and/or group
                       of the existing log file is used.

     mode              File mode (in octal) to use for created log files and

     count             The number of archives to be kept besides the log file

     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 '*', or set to '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 'B' (binary) flag is set or the -F option is
                       specified.  This prevents newsyslog from rotating files
                       consisting solely of a message indicating that the log
                       file has been turned over.

     when              The when field can consist of an interval, a specific
                       time, or both.  If the when field consists of an aster-
                       isk ('*'), log rotation will depend only on the con-
                       tents of the size field.  Otherwise, the when field
                       consists of an optional interval in hours, possibly
                       followed by an '@'-sign and a time in a restricted ISO
                       8601 format or by a '$'-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 satis-
                       fied for the rotation to take place.

                       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 implementa-
                       tion, 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 cur-
                       rent date; optional time fields default to midnight.
                       For example, if today is January 22, 1999, the follow-
                       ing date specifications are all equivalent:


                       Day, week and month time format: The lead-in character
                       for day, week and month specification is a dollar sign
                       ($).  The particular format of day, week and month
                       specification is: [DHH], [Ww[DHH]], and [Mdd[DHH]],
                       respectively.  Optional time fields default to mid-
                       night.  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 let-
                                     ter L or l to specify the last day of the

                       Some examples:
                             $D0     rotate every night at midnight (same as
                             $D23    rotate every day at 23:00 hr (same as
                             $W0D23  rotate every week on Sunday at 23:00 hr
                             $W5D16  rotate every week on Friday at 16:00 hr
                             $M1D0   rotate on 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 the month at
                                     6:00 hr (same as @05T06)

     flags             The optional flags field specifies if the archives
                       should have any special processing done to the archived
                       log files.  The 'Z' flag will make the archive files
                       compressed to save space using gzip(1) or compress(1),
                       depending on compilation options.  The 'B' flag means
                       that the file is a binary file, and so the ASCII mes-
                       sage which newsyslog inserts to indicate the fact that
                       the logs have been turned over should not be included.
                       The 'M' flag marks this entry as a monitored log file.
                       The 'F' flag specifies that symbolic links should be

     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 'M' flag is set.

     pid_file          This optional field specifies a file containing the PID
                       of a process to send a signal (usually SIGHUP) to
                       instead of /var/run/syslog.pid.

     signal            Specify the signal to send to the process instead of
                       SIGHUP.  Signal names must start with ``SIG'' and be
                       the signal name, not the number, e.g., SIGUSR1.

     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 ('"').  The empty string,
                       '""', can be used to prevent newsyslog from sending a
                       signal or running a command.  You cannot specify both a
                       command and a PID file.  NOTE: If you specify a command
                       to be run, newsyslog will not send a SIGHUP to

     /etc/newsyslog.conf  default configuration file

     compress(1), gzip(1), syslog(3), syslogd(8)

     Theodore Ts'o, MIT Project Athena
     Copyright 1987, Massachusetts Institute of Technology

BSD                           September 16, 2014                           BSD