Provided by: bsdutils_2.37.2-4ubuntu3.4_amd64 bug


       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., <13>).

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

           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. Examples:

              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(1) 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 RFC 5424 <> 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.

           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 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 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,, 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.

           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

           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, then logger will detect if the init process is
           systemd(1), 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


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


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


       The logger command was originally written by University of California in 1983-1993 and
       later rewritten by Karel Zak <>, Rainer Gerhards <>,
       and Sami Kerola <>.


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


       For bug reports, use the issue tracker at


       The logger command is part of the util-linux package which can be downloaded from Linux
       Kernel Archive <>.