Content
Data
license:
Version:
Developer / owner:
Craig H. Rowland (original C version)
Paul Slootman (Perl translated version)
Short description:
Manual page and help for the logtail linux command. The logtail program reads the file specified in the parameter (which is usually a log file) and outputs to standard output the part that it has not yet read during its previous run. It reads a sufficient number of bytes of data, assuming that changes made to the file have only been added as new characters.
Man page output
man logtailLOGTAIL(8) logtail manual LOGTAIL(8)
NAME
logtail - print log file lines that have not been read
SYNOPSIS
logtail [-t] -flogfile [-ooffsetfile]
DESCRIPTION
logtail reads a specified file (usually a log file) and writes to the stan‐
dard output that part of it which has not been read by previous runs of
logtail. It prints the appropriate number of bytes from the end of log‐
file, assuming that all changes that are made to it are to add new charac‐
ters to it.
logfile must be a plain file. A symlink is not allowed.
logtail stores the information about how much of it has already been read
in a separate file called offsetfile. offsetfile can be omitted. If omit‐
ted, the file named logfile.offset in the same directory which contains
logfile is used by default.
If offsetfile is not empty, the inode of logfile is checked. If the inode
is changed, logtail simply prints the entire file. If the inode is not
changed but logfile is shorter than it was at the last run of logtail, it
writes a warning message to the standard output.
OPTIONS
-f logfile to be read after offset
-o offsetfile stores offset of previous run
-t test mode - do not change offset in offsetfile
RETURN VALUES
0 successful
65 cannot get the size of logfile
66 logfile does not exist, is not a plain file, or is not readable
73 cannot write offsetfile
AUTHOR
The original logtail was written in C by Craig H. Rowland <crow‐
land@psionic.com>. This version of logtail is a Perl reimplementation by
Paul Slootman <paul@debian.org>. Enhanced by the Debian Logcheck Team
<logcheck@packages.debian.org>.
This manual was written by Oohara Yuuma <oohara@libra.interq.or.jp>.
SEE ALSO
logcheck(8)
Debian Fri, 19 Nov 2004 LOGTAIL(8)
Help output
sudo logtail --help/usr/sbin/logtail version [unknown] calling Getopt::Std::getopts (version 1.12 [paranoid]),
running under Perl version 5.28.1.
Usage: logtail [-OPTIONS [-MORE_OPTIONS]] [--] [PROGRAM_ARG1 ...]
The following single-character options are accepted:
With arguments: -f -o
Boolean (without arguments): -t
Options may be merged together. -- stops processing of options.
Space is not required between options and their arguments.
[Now continuing due to backward compatibility and excessive paranoia.
See 'perldoc Getopt::Std' about $Getopt::Std::STANDARD_HELP_VERSION.]
No logfile to read. Use -f [LOGFILE].
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