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.Dd Oct 13, 2019
.Dt logger 1
.Os "sysklogd (2.0)"
.Sh NAME
.Nm logger
.Nd Send messages to system log, or a log file
.Sh SYNOPSIS
.Nm
.Op Fl chsv
.Op Fl f Ar FILE
.Op Fl p Ar PRIO
.Op Fl r Ar SIZE:NUM
.Op Fl t Ar TAG
.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, which is the
automatically log rotated.  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 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 h
Show program help.
.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 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 syslog 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 /var/run/log -compact
.It Ar FILE
If a log file is enabled, using
.Fl f Ar FILE ,
then this file is opened and written to by
.Nm .
With log file rotation,
.Fl r Ar SIZE:NUM ,
this means
.Nm
also creates
.Pa FILE.1 FILE.2 FILE.3.gz
etc.
.It Pa /var/run/log
Socket to connect to for communicating with
.Xr syslogd 8 .
In older implementations
.Pa /dev/log
was used.  This means this version of
.Nm
is not compatible with older releases, or other (local) syslog servers.
.El
.Sh SEE ALSO
.Xr syslog 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 and log file rotation.
.Sh AVAILABILITY