which.rb

#!/usr/bin/env ruby
# vim: set fileencoding=utf-8 :
$VERBOSE = true
=begin
`which' command for Ruby libraries.
=end

lib = ARGV.shift
exts = %w/ .rb .so .dll /
puts $LOAD_PATH.map{|path|
  exts.map{|e| File.join path, lib + e }
}.flatten.find{|path| File.exist? path }