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 .

              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. <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
              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.

       --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
              systemd.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.

              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
              attempted.

       --no-act
              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.

       --octet-count
              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
              connections.

       -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.

       --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
              constructed 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 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"

              produces:

                <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.


       --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 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
              return value 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.

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

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

AUTHORS
       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⟩.

AVAILABILITY
       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-
       linux/⟩.



util-linux                       November 2015                       LOGGER(1)