From: Joel VanderWerf <joelvanderwerf@...>
Date: 2010-09-09T12:32:14+09:00
Subject: Re: different in single star(*) and double stars(**)?

Zhenning Guan wrote:
> # Load any custom rakefile extensions
> deprecated_paths =
> Dir["#{RAILS_ROOT}/vendor/plugins/*/tasks/**/*.rake"].sort
> 
> the code in rails. and what's the different * and **?

There is a brief explanation in the docs for the glob method:

$ ri Dir.glob | cat
-------------------------------------------------------------- Dir::glob
      Dir.glob( pattern, [flags] ) => array
      Dir.glob( pattern, [flags] ) {| filename | block }  => nil
------------------------------------------------------------------------
      Returns the filenames found by expanding pattern which is an Array
      of the patterns or the pattern String, either as an array or as
      parameters to the block. Note that this pattern is not a regexp
      (it's closer to a shell glob). See File::fnmatch for the meaning
      of the flags parameter. Note that case sensitivity depends on your
      system (so File::FNM_CASEFOLD is ignored)

      <code>*</code>:     Matches any file. Can be restricted by other
                          values in the glob. * will match all files; c*
                          will match all files beginning with c; *c will
                          match all files ending with c; and c will
                          match all files that have c in them (including
                          at the beginning or end). Equivalent to / .*
                          /x in regexp.

      <code>**</code>:    Matches directories recursively.

(There are also some examples... see if you can run ri to see them.)