Linen

Linen is a framework for creating applications that use a command line interface. It features a simple plugin system, readline integration for history and completion, and other features.

Example Script

The simplest example is the math.rb script in the distribution. It defines a simple plugin and command that allows you to do basic math on two floating point numbers. Drop that code into a file, then start it: 

superx ~/linen > ruby example.rb 
math >

You can then start exploring by issuing the help command. Be sure to check out the host.rb example for a more in-depth look at what you can do with Linen.

Download

You've got options! Linen is available as a gem, so a simple gem install linen should get you the newest version. You can also download archives from RubyForge or from this Trac:

License

Linen is released under the terms of the BSD license. See here for the actual license text.