def install(src, dest, options = {})
    fu_check_options options, OPT_TABLE['install']
    fu_output_message "install -c#{options[:preserve] && ' -p'}#{options[:mode] ? (' -m 0%o' % options[:mode]) : ''} #{[src,dest].flatten.join ' '}" if options[:verbose]
    return if options[:noop]
    fu_each_src_dest(src, dest) do |s, d, st|
      unless File.exist?(d) and compare_file(s, d)
        remove_file d, true
        copy_file s, d
        File.utime st.atime, st.mtime, d if options[:preserve]
        File.chmod options[:mode], d if options[:mode]
      end
    end
  end
Options: mode preserve noop verbose

If +src+ is not same as +dest+, copies it and changes the permission
mode to +mode+.  If +dest+ is a directory, destination is +dest+/+src+.
This method removes destination before copy.

FileUtils.install 'ruby', '/usr/local/bin/ruby', :mode => 0755, :verbose => true
FileUtils.install 'lib.rb', '/usr/local/lib/ruby/site_ruby', :verbose => true