rmdir(remove directory)
rmdir(remove directory)功能说明：删除目录。
语 法：rmdir [-p][--help][--ignore-fail-on-non-empty][--verbose][--version][目录...]
补充说明：当有空目录要删除时，可使用rmdir指令。
参 数：
-p或--parents 删除指定目录后，若该目录的上层目录已变成空目录，则将其一并删除。
--help 在线帮助。
--ignore-fail-on-non-empty 忽略非空目录的错误信息。
--verbose 显示指令执行过程。
--version 显示版本信息。
rmdir
rmdir [options] directories
Delete the named directories (not the contents). directories are deleted from the parent directory and must be empty (if not, rm -r can be used instead). See also mkdir.
Options
Print a help message and then exit.
Ignore failure to remove directories that are not empty.
Remove directories and any intervening parent directories that become empty as a result. Useful for removing subdirectory trees.
Verbose mode; print message for each directory as it is processed.
Print version information and then exit.