FACILITIES AND LEVELS
enter messages into the system log
makes entries in the system log.
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
Use datagrams (UDP) only. By
default the connection is tried to the syslog port defined
in /etc/services, which is often 514 .
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>").
Log the contents of the
specified file. This option cannot be combined with a
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
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:
MESSAGE=The dogs bark, but the caravan goes on.
−−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
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.
Causes everything to be done
except for the write the log message to the system log,
remove connection or journal. This options is usable
together with −−stderr for testing
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
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).
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,
headers 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.
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.
Use the specified port.
When this option is not specified, the port defaults to
syslog for udp and to syslog-conn for tcp connections.
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
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.
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 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
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
Output the message to standard
error as well as to the system log.
Use stream (TCP) only. By
default the connection is tried to the syslog-conn
port defined in /etc/services, which is often
Mark every line to be logged
with the specified tag.
Write to the specified
socket instead of to the system log socket.
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
mode is auto. When errors are not enabled lost
messages 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 (−).
Display version information and
Display help text and exit.
logger utility exits 0 on success, and >0 if an
FACILITIES AND LEVELS
priority order and intended purposes of these facilities and
levels, see syslog(3).
logger −p local0.notice −t HOSTIDM −f
logger −n loghost.example.com System rebooted
logger command is expected to be IEEE Std 1003.2
command is part of the util-linux package and is available