A Java log tailer: A tool to view log files

Download JLogTailer.jar (39kb)

A Java log tailer with regular expression features

JLogTailer animated screenshot

JLogTailer allows the viewing of any log file entries in real time. For example, you can fire up this program, point it at your server's log file and it will display new lines that are added to it in real time. This is particularly useful if you want to tinker around with stuff and need to see what's going into the end of your log files there and then, without having to faff about with the command line. More than one log file can be 'tailed' if desired.

How to run the log tailer

To run JLogTailer, you simple type the following:

java -jar JLogTailer.jar org.jibble.logtailer.JLogTailerMain

Alternatively, you may be able to do just the following:

java -jar JLogTailer.jar

If your system is set up correctly, then you may even be able to run the server by double-clicking on the JLogTailer.jar file.

Note that you must have installed a Java Runtime Environment in order to run Java programs. Please read this guide on How to set up Java if you need help. This program will require Java 1.4 or later.

When you start up the program, you can start tailing a new log by using the File menu and opening a log file to tail. This will create a new internal window to display the activity of the log file. Any new lines that are added to the end of the log file will appear in the internal window for this log.

If a log file is deleted or cleared, then this event is displayed and the program will still log new lines that appear in the log file when it is recreated or has new lines appended to it.

The jar file contains the program and its source code.

Regular expression log tailer

Each log file that you are tailing can be associated with an ordered list of highlighting rules. Each rule specifies a regular expression and when a line matches this, it is processed accordingly. This screenshot shows a rule specification for a PircBot log file. It causes all lines that are sent to the IRC server to be made bold and blue.

JLogTailer highlighting rule

Miscellaneous jibble

JLogTailer was inspired by logtailer, a C program written by Adam Sampson. You might want to have a look at that if you want to be able to tail logs via a terminal screen.

If you are a user of IntelliJ IDEA, you may be interested to note that Mark Lussier has created a LogTailer Plugin, which is based on JLogTailer.

As usual, please send all feature requests, feedback and bug reports to the email address at the bottom of this page.


This software product is OSI Certified Open Source Software, available under the GNU General Public License (GPL). Since the GPL may be too restrictive for use in proprietary applications, a commercial license is also provided.

Purchase a commercial license for this software.


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Copyright Paul Mutton 2001-2013
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