Useful Code/Commands

IRB

1. irb --readline -r irb/completion
   
   When you press Tab, Irb will attempt code completion. If there are several possible matches press Tab twice and Ruby will give you a complete list of them. This works for jirb in JRuby but with some slight differences.

JRuby/Swing

1. lab = JLabel.new lab.opaque = true lab.background = Color::CYAN
   
   If you want to give a label a background colour, set the opaque property to true and then apply the colour.

Miscellaneous

1. ARGV.clear
   
   Clears out the command line argument array.
   
   
2. string = <<-STRING_END ... STRING_END
   
   Here documents begin with << or <<- followed by a constant which is the string terminator. If the document begins with << then the terminator must be in the left-most column.