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Rainbow extends ruby String class adding methods to wrap the string with ANSI escape codes.


Rainbow adds following methods to String class:

  • foreground(color) (with color and colour aliases)
  • background(color)
  • reset
  • bright
  • italic (not well supported by terminal emulators).
  • underline
  • blink
  • inverse
  • hide.

Each of those methods returns string wrapped with some ANSI codes so you can chain calls as in example above.

Color can be one of following symbols:

:black, :red, :green, :yellow, :blue, :magenta, :cyan, :white, :default

If you have 256-colors capable terminal you can also specify color in RGB which will find the nearest match from 256 colors palette:

"Jolacz".color(115, 23, 98)

For support on Windows, you should install the following gems:

gem install windows-pr win32console

If the gems aren't installed strings are simply returned unaltered.

Rainbow can be disabled globally by setting:

Sickill::Rainbow.enabled = false

It will be disabled by default if it detects that STDOUT is not a TTY.


gem install rainbow


require 'rainbow'
puts "this is red".foreground(:red) + " and " + "this on yellow bg".background(:yellow) + " and " + "even bright underlined!".underline.bright

Rails Usage

You're probably wanting to add colour to your logs. To do so you must explicity enable rainbow because it will detect that STDOUT (ie: the log file) is not a TTY. To make things easy, create the file config/initializers/rainbow.rb and include the following:

require 'rainbow'
Sickill::Rainbow.enabled = true


  • Marcin Kulik
  • Xavier Nayrac