logger - a shell command interface to the syslog(3)
system log module
makes entries in the system log. It provides a shell command
interface to the syslog(3)
system log module.
- -d, --udp
- Use datagram (UDP) only. By default the connection is tried
to the syslog port defined in /etc/services, which is often
- -h, --help
- Display help text and exit.
- -i, --id
- Log the process ID of the logger process with each
- -n, --server server
- Write to the specified remote syslog server instead
of to the builtin syslog routines. Unless --udp or --tcp is
specified, logger will first try to use UDP, but if thist fails a
TCP connection is attempted.
- -P, --port port
- Use the specified port.
- -f, --file file
- Log the contents of the specified file. This option
cannot be combined with a command-line message.
- -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
- Look for a syslog prefix on every line read from standard
input. This prefix is a number within angle brackets that contains both
the facility and the level. This decimal prefix is constructed by
multiplying the facility by 8 and then adding the level. Thus, for
example, local0.info, 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 -p priority.
This option doesn't affect a command-line message.
- -s, --stderr
- Output the message to standard error as well as to the
- -T, --tcp
- Use stream (TCP) only. By default the connection is tried
to the syslog-conn port defined in /etc/services, which is often
- -t, --tag tag
- Mark every line to be logged with the specified
- -u, --socket socket
- Write to the specified socket instead of to the
builtin syslog routines.
- --journald [file]
- Write systemd journal entry. The entry is read from
stdin or input file. Each new line must begin with a field
that is accepted by journald, see systemd.journal-fields(7) for
details. Use of MESSAGE_ID field is generally good idea, as they make
finding entries easy.
$ printf "%s\n%s\n%s\n" MESSAGE_ID=86184c3b1aa444f58ebe7b30fec1438b DOGS=bark "CARAVAN=goes on" | logger --journald
$ 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.
- -V, --version
- Display version information and exit.
- End the argument list. This is to allow the message
to start with a hyphen (-).
- Write this message to the log; if not specified, and
the -f flag is not provided, standard input is logged.
utility exits 0 on success, and >0 if an error occurs.
Valid facility names are: auth
information of a sensitive nature),
generated from user process),
(deprecated synonym for
Valid level names are:
(deprecated synonym for
(deprecated synonym for emerg
(deprecated synonym for warning
). For the priority order and intended
purposes of these levels, see syslog(3)
logger System rebooted
logger -p local0.notice -t HOSTIDM -f /dev/idmc
logger -n loghost.example.com System rebooted
command is expected to be IEEE Std 1003.2
The logger command is part of the util-linux package and is available from