logger

LOGGER(1)                        User Commands                       LOGGER(1)

NAME
       logger - enter messages into the system log

SYNOPSIS
       logger [options] [message]

DESCRIPTION
       logger makes entries in the system log.

       When  the  optional  message  argument is present, it is written to the
       log.  If it is not present, and the -f option is not given either, then
       standard input is logged.

OPTIONS
       -d, --udp
              Use datagrams (UDP) only.  By default the connection is tried to
              the syslog port defined in /etc/services, which is often 514 .

       -e, --skip-empty
              When processing files, empty lines will  be  ignored.  An  empty
              line is defined to be a line without any characters. Thus a line
              consisting only of whitespace is  NOT  considered  empty.   Note
              that when the --prio-prefix option is specified, the priority is
              not part of the line. Thus an empty line in this mode is a  line
              that  does  not  have  any  characters  after the priority (e.g.
              "<13>").

       -f, --file file
              Log the contents of the specified file.  This option  cannot  be
              combined with a command-line message.

       -i     Log the PID of the logger process with each line.

       --id[=id]
              Log  the  PID  of  the  logger process with each line.  When the
              optional argument id is specified, then it is  used  instead  of
              the  logger  command's PID.  The use of --id=$$ (PPID) is recom-
              mended in scripts that send several messages.

       --journald[=file]
              Write a systemd journal entry.  The entry is read from the given
              file,  when specified, otherwise from standard input.  Each line
              must begin with a field that is accepted by journald;  see  sys-
              temd.journal-fields(7)  for  details.   The  use of a MESSAGE_ID
              field is generally a good idea,  as  it  makes  finding  entries
              easy.  Examples:

                  logger --journald <<end
                  MESSAGE_ID=67feb6ffbaf24c5cbec13c008dd72309
                  MESSAGE=The dogs bark, but the caravan goes on.
                  DOGS=bark
                  CARAVAN=goes on
                  end

                  logger --journald=entry.txt

              Notice that --journald will ignore values of other options, such
              as priority.  If priority is needed it must be within input, and
              use  PRIORITY  field.   The  simple execution of journalctl will
              display MESSAGE field.  Use journalctl --output  json-pretty  to
              see rest of the fields.

       --msgid MSGID
              Sets  the  RFC5424 MSGID field. Note that the space character is
              not permitted inside of MSGID.  This  option  is  only  used  if
              --rfc5424  is  specified  as  well.  Otherwise,  it  is silently
              ignored.

       --no-act
              Causes everything to be done except for the write the  log  mes-
              sage  to  the  system  log,  remove  connection or journal. This
              options is usable together with --stderr for testing purpose.

       --size size
              Sets the maximum permitted message size to size. The default  is
              1KiB characters, which is the limit traditionally used and spec-
              ified in RFC 3164. With RFC 5424, this limit has  become  flexi-
              ble.  A  good assumption is that RFC 5424 receivers can at least
              process 4KiB messages.

              Most receivers accept larger than 1KiB message over any type  of
              syslog  protocol.  As  such, the --size option affects logger in
              all cases (not only when --rfc5424 was used).

              Note: the message size limit limits the  overall  message  size,
              including  the  syslog  header.  Header  sizes vary depending on
              options selected and hostname length. As a rule of thumb,  head-
              ers  are  usually  not  longer  than  50  to 80 characters. When
              selecting maximum message size, it is important to  ensure  that
              the  receiver  supports the max size as well, otherwise messages
              may become truncated. Again, as a rule of thumb two to four  KiB
              message  size  should  generally  be OK, whereas anything larger
              should be verified to work.

       -n, --server server
              Write to the specified remote syslog server instead  of  to  the
              system  log  socket.  Unless --udp or --tcp is specified, logger
              will first try to use UDP, but if thist fails a  TCP  connection
              is attempted.

       -P, --port port
              Use  the specified port.  When this option is not specified, the
              port defaults to syslog for udp and to syslog-conn for tcp  con-
              nections.

       -p, --priority priority
              Enter the message into the log with the specified priority.  The
              priority may be specified numerically  or  as  a  facility.level
              pair.   For example, -p local3.info logs the message as informa-
              tional in the local3 facility.  The default is user.notice.

       --prio-prefix
              Look for a syslog prefix on every line read from standard input.
              This  prefix  is  a  decimal  number  within angle brackets that
              encodes both the facility and the level.   The  number  is  con-
              structed  by  multiplying  the facility by 8 and then adding the
              level.   For  example,  local0.info,  meaning  facility=16   and
              level=6, becomes <134>.

              If  the  prefix  contains  no facility, the facility defaults to
              what is specified by the -p option.  Similarly, if no prefix  is
              provided, the line is logged using the priority given with -p.

              This option doesn't affect a command-line message.

       --rfc3164
              Use  the  RFC  3164  BSD syslog protocol to submit messages to a
              remote server.

       --rfc5424[=without]
              Use the RFC 5424 syslog protocol to submit messages to a  remote
              server.   The optional without argument can be a comma-separated
              list of the following values: notq, notime,  nohost.   The  notq
              value  suppresses the time-quality structured data from the sub-
              mitted message.  (The time-quality information shows whether the
              local   clock  was  synchronized  plus  the  maximum  number  of
              microseconds the timestamp might  be  off.)   The  notime  value
              (which  implies  notq)  suppresses the complete sender timestamp
              that is in ISO-8601 format, including microseconds and timezone.
              The  nohost value suppresses gethostname(2) information from the
              message header.

              The RFC 5424 protocol has been the default for logger since ver-
              sion 2.26.

       --octet-count
              Use  the RFC 6587 octet counting framing method for sending mes-
              sages. When this option is not used, the default is  no  framing
              on UDP, and RFC6587 non-transparent-framing (also known as octet
              stuffing) on TCP.

       -s, --stderr
              Output the message to standard error as well as  to  the  system
              log.

       -T, --tcp
              Use  stream  (TCP)  only.  By default the connection is tried to
              the syslog-conn port defined in /etc/services,  which  is  often
              601.

       -t, --tag tag
              Mark every line to be logged with the specified tag.

       -u, --socket socket
              Write  to  the  specified  socket  instead  of to the system log
              socket.

       --socket-errors[=mode]
              Print errors about Unix socket connections.  The mode can  be  a
              value  of  off,  on, or auto.  When the mode is auto logger will
              detect if the init process is systemd, and if so  assumption  is
              made  /dev/log  can  be  used early at boot.  Other init systems
              lack of /dev/log will not cause errors that  is  identical  with
              messaging  using  openlog(3)  system call.  The logger(1) before
              version 2.26 used openlog, and hence was inable to detected loss
              of messages sent to Unix sockets.

              The default mode is auto.  When errors are not enabled lost mes-
              sages are not communicated and will result to successful  return
              value of logger(1) invocation.

       --     End  the argument list.  This allows the message to start with a
              hyphen (-).

       -V, --version
              Display version information and exit.

       -h, --help
              Display help text and exit.

RETURN VALUE
       The logger utility exits 0 on success, and >0 if an error occurs.

FACILITIES AND LEVELS
       Valid facility names are:

              auth
              authpriv   for security information of a sensitive nature
              cron
              daemon
              ftp
              kern       cannot be generated from userspace process, automatically converted to user
              lpr
              mail
              news
              syslog
              user
              uucp
              local0
                to
              local7
              security   deprecated synonym for auth

       Valid level names are:

              emerg
              alert
              crit
              err
              warning
              notice
              info
              debug
              panic     deprecated synonym for emerg
              error     deprecated synonym for err
              warn      deprecated synonym for warning

       For the priority order and intended purposes of  these  facilities  and
       levels, see syslog(3).

EXAMPLES
       logger System rebooted
       logger -p local0.notice -t HOSTIDM -f /dev/idmc
       logger -n loghost.example.com System rebooted

SEE ALSO
       syslog(3), journalctl(1), systemd.journal-fields(7)

STANDARDS
       The  logger  command is expected to be IEEE Std 1003.2 ("POSIX.2") com-
       patible.

AVAILABILITY
       The logger command is part of the util-linux package and  is  available
       from  Linux  Kernel Archive <ftp://ftp.kernel.org/pub/linux/utils/util-
       linux/>.

util-linux                        March 2015                         LOGGER(1)
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