def cd(dir, options = {}, &block) # :yield: dir
    fu_check_options options, OPT_TABLE['cd']
    fu_output_message "cd #{dir}" if options[:verbose]
    Dir.chdir(dir, &block)
    fu_output_message 'cd -' if options[:verbose] and block
  end
Options: verbose

Changes the current directory to the directory +dir+.

If this method is called with block, resumes to the old
working directory after the block execution finished.

FileUtils.cd('/', :verbose => true)   # chdir and report it

FileUtils.cd('/') do  # chdir
[...]               # do something
end                   # return to original directory