what is “$:” in ruby?

Question

Usually be seen in .gemspec file. eg. i18n.gemspec.

$: << File.expand_path(\'../lib\', __FILE__)

Answer 1

$: is equivalent to $LOAD_PATH, i.e. the list of directories that you can require files from without giving a more specific path. You'll find the Ruby QuickRef useful for other predefined variables you may run into.