有时出于好奇，或者出于做一些不同事情的实际愿望，您可能会尝试在Windows系统上为文件夹使用一些不寻常的名称，但结果不一。有鉴于此，今天的超级用户问答帖子回答了一位好奇读者的问题。

今天的问答环节是由SuperUser提供的，SuperUser是Stack Exchange的一个分支，是一个由社区驱动的问答网站分组。

消息窗口截图由Ben N（超级用户）提供。

问题

超级用户读者EdwardBlack想知道为什么不能命名文件夹。在他的Windows 7系统上：

I just noticed that it is not possible to name a folder ._. on my Windows 7 system. It gets renamed to ._ instead. Sometimes it disappears just after naming it, but then reappears after refreshing the view. Windows seems to have a problem with dots at the end of a filename. Why is this?

为什么不能命名文件夹。\u。在Windows7中？

答案

超级用户贡献者Ben N为我们提供了答案：

Windows normally requires files to have either no extension or an extension that is at least one character long. It does not like zero length extensi*** (i.e. file names that end with a period). Folders can have extensi*** too, therefore, Windows does not let their names end with a period.

Source: From the article linked to by DavidPostill:

• Use a period to separate the base file name from the extension in the name of a directory or file.

If you try to end a file or directory name with a period, Windows just assumes that you did not want an extension and thus removes it (even if you create it with the md command in a command prompt window).

Danger Zone

If you really want a folder name to end with period, you will need to use the magic raw name override sequence of \\?\. In a command prompt window, md \\?\C:\path\to\container\._. will indeed create a folder named ._., but lots of programs will have problems with it, even Windows Explorer:

Such a directory can only be removed with the rd command followed by its \\?\ name, or renamed with its short (8.3, dir /x) name.

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