Misc

• Write ruby -w safe code. ^[link]

• Avoid hashes as optional parameters. Does the method do too much? (Object initializers are exceptions for this rule). ^[link]

• Avoid methods longer than 10 LOC (lines of code). Ideally, most methods will be shorter than 5 LOC. Empty lines do not contribute to the relevant LOC. ^[link]

• Avoid parameter lists longer than three or four parameters. ^[link]

• If you really need "global" methods, add them to Kernel and make them private. ^[link]

• Use module instance variables instead of global variables. ^[link]

  # bad
  $foo_bar = 1
  
  # good
  module Foo
    class << self
      attr_accessor :bar
    end
  end
  
  Foo.bar = 1
  

• Use OptionParser for parsing complex command line options and ruby -s for trivial command line options. ^[link]

• Prefer Time.now over Time.new when retrieving the current system time. ^[link]

• Code in a functional way, avoiding mutation when that makes sense. ^[link]

• Do not mutate parameters unless that is the purpose of the method. ^[link]

• Avoid more than three levels of block nesting. ^[link]

• Be consistent. In an ideal world, be consistent with these guidelines. ^[link]

• Use common sense. ^[link]