.TH LOGTAIL 8 "Fri, 19 Nov 2004" "Debian" "logtail manual"
.SH NAME
logtail \- print log file lines that have not been read
.SH SYNOPSIS
.B logtail
.RI [\-t]
.BI \-f logfile
.RI [\-o offsetfile ]
.SH DESCRIPTION
.B logtail
reads a specified file (usually a log file) and writes
to the standard output that part of it
which has not been read by previous runs of
.BR logtail .
It prints the appropriate number of bytes from the end of
.IR logfile ,
assuming that all changes that are made to it are to add new
characters to it.
.P
.I logfile
must be a plain file.  A symlink is not allowed.
.P
.B logtail
stores the information about how much of it has already been read
in a separate file called
.IR offsetfile .
.I offsetfile
can be omitted.  If omitted, the file named
.I logfile.offset
in the same directory which contains
.I logfile
is used by default.
.P
If
.I offsetfile
is not empty, the inode of
.I logfile
is checked.  If the inode is changed,
.B logtail
simply prints the entire file.
If the inode is not changed but
.I logfile
is shorter than it was at the last run of
.BR logtail ,
it writes a warning message to the standard output.
.SH OPTIONS
.TP
.B \-f
.I logfile
to be read after offset
.TP
.B \-o
.I offsetfile
stores offset of previous run
.TP
.B \-t
test mode - do not change offset in
.I offsetfile
.SH RETURN VALUES
.IP 0
successful
.IP 65
cannot get the size of
.IR logfile
.IP 66
.I logfile
does not exist, is not a plain file, or is not readable
.IP 73
cannot write
.I offsetfile
.SH AUTHOR
The original
.B logtail
was written in C by Craig H. Rowland <crowland@psionic.com>.
This version of
.B logtail
is a Perl reimplementation by Paul Slootman <paul@debian.org>.
Enhanced by the Debian Logcheck Team <logcheck@packages.debian.org>.
.P
This manual was written by Oohara Yuuma <oohara@libra.interq.or.jp>.
.SH SEE ALSO
.BR logcheck (8)