File::Tail for Ruby


This is a small ruby library that allows it to “tail” files in Ruby, including following a file, that still is growing like the unix command ‘tail -f’ can.


The latest version of File::Tail (file-tail) can be found at

Online Documentation should be located at


To install file-tail via its gem type:

# gem install file-tail

To install from the source repository, just type into the command line as root:

# rake install


File::Tail is a module in the File class. A lightweight class interface for logfiles can be seen under File::Tail::Logfile.

Direct extension of File objects with File::Tail works like that: do |log|
   log.interval = 10
   log.tail { |line| puts line }

It’s also possible to mix File::Tail in your own File classes (see also File::Tail::Logfile):

 class MyFile < File
   include File::Tail
 log ="myfile")
 log.interval = 10
 log.tail { |line| print line }

The forward/backward method returns self, so it’s possible to chain methods together like that:

 log.backward(10).tail { |line| puts line }

A command line utility named rtail, that uses File::Tail is provided as well.


To create the documentation of this module, type

$ rake doc

and the API documentation is generated.

In the examples direcotry is a small example of tail and pager program that use this module. You also may want look at the end of file/tail.rb for a little example.


Florian Frank


This is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License Version 2 as published by the Free Software Foundation: