Colors & Hash Rockets in IRB
Latest commit de3ba17 Mar 2, 2016 @janlelis Release 1.0.2

FancyIrb version

  • Colorizes IRB prompts, errors, $stderr and $stdout
  • Uses "Hash Rockets" (# =>) to display IRB results


require 'fancy_irb'

You can pass an options hash. These are the default values:

  :rocket_mode     => true,   # activate or deactivate #=> rocket
  :rocket_prompt   => '#=> ', # prompt to use for the rocket
  :result_prompt   => '=> ',  # prompt to use for normal output
  :east_asian_width => false, # set to true if you have double-width characters (slower)
  :colorize => {              # colors hash. Set to nil to deactivate colors
    :rocket_prompt => [:blue],
    :result_prompt => [:blue],
    :input_prompt  => nil,
    :irb_errors    => [:red, :clean],
    :stderr        => [:red, :bright],
    :stdout        => nil,
    :input         => nil,

Rocket mode means: Output result as comment if there is enough space left on the terminal line and stdout does not output more than the current terminal height.

For more information on which colors can be used, see the paint documentation.


Windows Support

You will need ansicon or ConEmu.

Wrong display widths?

When using double-width unicode chars, you should set :east_asian_width to true. It is not activated by default, because of its performance impact.

Known bugs

Not all stdin methods are patched properly to work with the rocket: The gems focuses on the often used ones


Inspired by the irb_rocket gem by genki.

Copyright (c) 2010-2012, 2015 Jan Lelis released under the MIT license.