sysklogd/man/logger.1

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.Dd Dec 7, 2019
.Dt LOGGER 1
.Os sysklogd v2.1
.Sh NAME
.Nm logger
.Nd Send messages to system log, or a log file
.Sh SYNOPSIS
.Nm
.Op Fl chinsv
.Op Fl d Ar SD
.Op Fl f Ar FILE
.Op Fl m Ar MSGID
.Op Fl p Ar PRIO
.Op Fl r Ar SIZE:NUM
.Op Fl t Ar TAG
.Op Fl u Ar SOCK
.Op Ar MESSAGE
.Sh DESCRIPTIOMN
.Nm
can be used to log messages to the system log daemon from a UNIX shell,
or script.  Optionally a stand-alone log file can be used, in which case
the
.Xr syslogp 3
API is still used but
.Nm syslogd
is bypassed.  This log file can also be automatically log rotated.
.Pp
Without a
.Ar MESSAGE
argument
.Nm
reads input from
.Ar stdin .
.Sh OPTIONS
This program follows the usual UNIX command line syntax:
.Bl -tag -width Ds
.It Fl c
Log to console
.Ql ( LOG_CONS )
if
.Fn syslog
fails to send message to
.Xr syslogd 8 .
.It Fl d Ar SD
Log this in the structured data (SD) field of an RFC5424 style log
message.  See
.Fl m
for caveats.  Also, please note that
.Ar sd
has to be passed as one argument and will require careful quoting when
used from the shell.
.It Fl f Ar FILE
Log file to write messages to, instead of syslog daemon.
.Nm
accepts
.Fl f-
as an alias for
.Ar stdout .
.It Fl i
Log the process id of the logger process with each line
.Ql ( LOG_PID ) .
.It Fl m Ar MSGID
The MSGID used for the message.  Requires RFC5424 support in
.Xr syslogd 8
for receiving the message and also for storing it properly in a log file
or sending remote in correctly formatted RFC5424 style.
.It Fl n
Open log file immediately
.Ql ( LOG_NDELAY ) .
.It Fl p Ar PRIO
Priority, numeric or
.Ar facility.severity
pair.
.It Fl r Ar SIZE:NUM
Controls log file rotation.
.Ar SIZE
denotes number of bytes before rotating, default: 200 kB.
.Ar NUM
denotes number of rotated files to keep when logging to a file, default:
5.
.It Fl s
Log to stderr as well as the system log.
.It Fl t Ar TAG
Log using the specified tag, default: username.
.It Fl u Ar SOCK
Log to UNIX domain socket
.Ar SOCK
instead of the default
.Pa /dev/log .
.It Fl v
Show program version.
.It Ar MESSAGE
Log message to write.  Remember to use single/double qoutes if calling
.Nm
from a shell prompt due to expansion the shell does.  If no message is
given
.Nm
will read from
.Ar stdin
until EOF.  In this mode every new row (newline separated) is converted
into an independent
.Xr syslogp 3
call.
.El
.Sh EXAMPLES
.Bd -unfilled -offset left
logger -t dropbear -p auth.notice "Successful login for user 'admin' from 1.2.3.4"
logger -t udhcpc -f /tmp/script.log "New lease 1.2.3.200 obtained for interface eth0"
.Ed
.Sh FILES
.Bl -tag -width /dev/log -compact
.It Ar FILE
If a custom log file is selected, using
.Fl f Ar FILE ,
then this file is opened and written to by
.Nm .
When log file rotation is enabled, using
.Fl r Ar SIZE:NUM ,
.Nm
creates
.Pa FILE.1 FILE.2 FILE.3.gz
etc.
.It Pa /dev/log
Socket used for communicating with
.Xr syslogd 8 .
When built on BSD
.Pa /var/run/log 
is used.
.El
.Sh SEE ALSO
.Xr syslogp 3
.Xr syslogd 8
.Sh AUTHORS
.Nm
was originally written by Joachim Nilsson to be a part of the
.Xr finit 1
system monitor (PID 1), where it is called
.Nm logit .
It is included here to complement
.Xr syslogd  8
and be extended upon in the sysklogd project.
.Sh STANDARDS
The
.Nm
command is expected to be IEEE Std 1003.2 ("POSIX.2") compatible, with
extensions for RFC5424 from NetBSD and custom log file and log file
rotation unique to the sysklogd project.