bionic (1) logger.1.gz

Provided by: bsdutils_2.31.1-0.4ubuntu3.7_amd64 bug

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
              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.

       --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

       --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.

       -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.

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/⟩.