LOGGER(1)                         User Commands                        LOGGER(1)

       logger - enter messages into the system log

       logger [options] [message]

       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.

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

              See also --server and --socket to specify where to connect.

       -e, --skip-empty
              Ignore empty lines when processing files.  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 prefix (e.g.,

       -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.

              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 recommended in
              scripts that send several messages.

              Note that the system logging infrastructure (for example systemd
              when listening on /dev/log) may follow local socket credentials to
              overwrite the PID specified in the message.  logger(1) is able to
              set those socket credentials to the given id, but only if you have
              root permissions and a process with the specified PID exists,
              otherwise the socket credentials are not modified and the problem
              is silently ignored.

              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
              systemd.journal-fields(7) for details.  The use of a MESSAGE_ID
              field is generally a good idea, as it makes finding entries easy.

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

                  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.

              To include newlines in MESSAGE, specify MESSAGE several times.
              This is handled as a special case, other fields will be stored as
              an array in the journal if they appear multiple times.

       --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.

       -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 this fails a TCP connection is

              Causes everything to be done except for writing the log message to
              the system log, and removing the connection or the journal.  This
              option can be used together with --stderr for testing purposes.

              Use the RFC 6587 octet counting framing method for sending
              messages.  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.

       -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

       -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 informational in
              the local3 facility.  The default is user.notice.

              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 constructed by
              multiplying the facility by 8 and then adding the level.  For
              example, local0.info, meaning facility=16 and level=6, becomes

              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.

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

              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 submitted message.  The time-quality information shows whether
              the local clock was synchronized plus the maximum number of
              microseconds the timestamp might be off.  The time quality is also
              automatically suppressed when --sd-id timeQuality is specified.

              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
              version 2.26.

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

       --sd-id name[@digits]
              Specifies a structured data element ID for an RFC 5424 message
              header.  The option has to be used before --sd-param to introduce
              a new element.  The number of structured data elements is
              unlimited.  The ID (name plus possibly @digits) is case-sensitive
              and uniquely identifies the type and purpose of the element.  The
              same ID must not exist more than once in a message.  The @digits
              part is required for user-defined non-standardized IDs.

              logger currently generates the timeQuality standardized element
              only.  RFC 5424 also describes the elements origin (with
              parameters ip, enterpriseId, software and swVersion) and meta
              (with parameters sequenceId, sysUpTime and language).  These
              element IDs may be specified without the @digits suffix.

       --sd-param name="value"
              Specifies a structured data element parameter, a name and value
              pair.  The option has to be used after --sd-id and may be
              specified more than once for the same element.  Note that the
              quotation marks around value are required and must be escaped on
              the command line.

                  logger --rfc5424 --sd-id zoo@123               \
                                   --sd-param tiger=\"hungry\"   \
                                   --sd-param zebra=\"running\"  \
                                   --sd-id manager@123           \
                                   --sd-param onMeeting=\"yes\"  \
                                   "this is message"


                <13>1 2015-10-01T14:07:59.168662+02:00 ws kzak - - [timeQuality
              tzKnown="1" isSynced="1" syncAccuracy="218616"][zoo@123
              tiger="hungry" zebra="running"][manager@123 onMeeting="yes"] this
              is message

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

              Most receivers accept messages larger than 1KiB 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 the
              selected options and the hostname length.  As a rule of thumb,
              headers are usually not longer than 50 to 80 characters.  When
              selecting a 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.

              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 unable to detected loss of messages
              sent to Unix sockets.

              The default mode is auto.  When errors are not enabled lost
              messages are not communicated and will result to successful exit
              status of logger(1) invocation.

       -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.

              See also --server and --socket to specify where to connect.

       -t, --tag tag
              Mark every line to be logged with the specified tag.  The default
              tag is the name of the user logged in on the terminal (or a user
              name based on effective user ID).

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

       --     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.

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

       Valid facility names are:

              authpriv   for security information of a sensitive nature
              kern       cannot be generated from userspace process,
                         automatically converted to user

              security   deprecated synonym for auth

       Valid level names are:

              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).

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

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

       The logger command was originally written by University of California in
       1983-1993 and later rewritten by Karel Zak ⟨kzak@redhat.com⟩, Rainer
       Gerhards ⟨rgerhards@adiscon.com⟩ and Sami Kerola ⟨kerolasa@iki.fi⟩.

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

       The logger command is part of the util-linux package and is available
       from Linux Kernel Archive ⟨https://www.kernel.org/pub/linux/utils/util-

util-linux                        November 2015                        LOGGER(1)