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 .
-e, --skip-empty
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 prior‐
ity 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>").
-f, --file file
Log the contents of the specified file. This option cannot be combined with a com‐
mand-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.
--journald[=file]
Write a systemd journal entry. The entry is read from the given file, when speci‐
fied, 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 MES‐
SAGE_ID field is generally a good idea, as it makes finding entries easy. Exam‐
ples:
logger --journald <.
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 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.
--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.
-s, --stderr
Output the message to standard error as well as to the system log.
-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.
-u, --socket socket
Write to the specified socket instead of to the system log socket.
--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 open‐
log(3) system call. The logger(1) before version 2.26 used openlog, and hence was
inable to detected loss of messages sent to Unix sockets.
The default mode is auto. When errors are not enabled lost messages are not commu‐
nicated and will result to successful return value of logger(1) invocation.
-- 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 sys‐
log(3).
EXAMPLES
logger System rebooted
logger -p local0.notice -t HOSTIDM -f /dev/idmc
logger -n loghost.example.com System rebooted
SEE ALSO
syslog(3), journalctl(1), 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 ⟨ftp://ftp.kernel.org/pub/linux/utils/util-linux/⟩.
util-linux March 2015 LOGGER(1)
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