为什么Windows上的cmd.exe shell使用正斜杠('/'')路径分隔符失败？

Question

就在我以为我已经看到了Windows路径问题时,我现在遇到的情况只有在使用'/'(正斜杠)作为路径分隔符时才会失败:

C:\temp\tcbugs>mkdir "dir1 with spaces"

C:\temp\tcbugs>echo hi > "dir1 with spaces"\foo.txt

C:\temp\tcbugs>type "dir1 with spaces\foo.txt"
hi

C:\temp\tcbugs>type "dir1 with spaces/foo.txt"
The system cannot find the file specified.

特别有趣的是它似乎是特定于cmd.exe shell而不是在PowerShell中出现(也不是在win32 API中):

PS C:\temp\tcbugs> type 'dir1 with spaces/foo.txt'
hi

另一个兴趣点是使用'cd'更改目录并使用'/'作为cmd.exe的路径分隔符确实有效:

C:\temp\tcbugs>mkdir dir2_no_spaces

C:\temp\tcbugs>cd ./dir2_no_spaces

C:\temp\tcbugs\dir2_no_spaces>cd ..

然而,我无法在网上或MSDN的常用文档中找到任何对此特定问题的引用:

命名文件,路径,命名空间

这引出了我的问题:为什么会发生这种情况,是否有一个明确的来源记录了这个怪癖？

更新:

dbenham指出,无论空格是否在目录名称中,问题都存在,因此在标题和问题正文中删除了对它的引用.还添加了一个有效的"cd ./"示例,而其他命令则没有.

Answer 1

编辑删除意见

无论Windows CMD.EXE是否应该支持路径中的正斜杠,事实上它有时会起作用,有时它不起作用,有时它似乎工作但却给出了错误的结果 - AKA是一个错误.

这是一些实验的时间:-)

所有测试都在Vista上运行

C:\>md "c:/temp/"

C:\>REM The forward slash works with MD!

C:\>echo hello world 1>>"c:/temp/test.txt"

C:\>REM Redirection works with forward slashes!

C:\>type "c:\temp\test.txt"
hello world

C:\>REM Of course TYPE works with back slashes

C:\>type "c:/temp/test.txt"
The system cannot find the file specified.

C:\>REM But forward slash version fails

C:\>type "c:/temp\test.txt"
hello world

C:\>REM But TYPE works with forward slash as long as last slash is back slash

C:\>dir "c:/temp/test.txt"
 Volume in drive C is OS
 Volume Serial Number is EE2C-5A11

 Directory of c:\temp

File Not Found

C:\>REM Note how DIR lists the directory with a \, yet fails to find any files

C:\>dir "c:/temp/*"
 Volume in drive C is OS
 Volume Serial Number is EE2C-5A11

 Directory of c:\temp

File Not Found

C:\>REM DIR Still fails with forward slashes

C:\>dir "c:/temp/"
 Volume in drive C is OS
 Volume Serial Number is EE2C-5A11

 Directory of c:\temp

05/09/2012  09:58 PM    <DIR>          .
05/09/2012  09:58 PM    <DIR>          ..
05/09/2012  09:58 PM                13 test.txt
               1 File(s)             13 bytes
               2 Dir(s)  337,001,615,360 bytes free

C:\>REM But forward slash works if no file is specified!

C:\>dir "c:/temp\test.txt"
 Volume in drive C is OS
 Volume Serial Number is EE2C-5A11

 Directory of c:\temp

05/09/2012  09:58 PM                13 test.txt
               1 File(s)             13 bytes
               0 Dir(s)  337,001,615,360 bytes free

C:\>REM And DIR works with forward slash as long as last slash is back slash


C:\>REM Now add another folder to the path hierarchy

C:\>md "c:/temp/temp/"

C:\>REM Still can create folder using forward slashes

C:\>copy "c:/temp/test.txt" "c:/temp/temp/"
The system cannot find the file specified.
        0 file(s) copied.

C:\>REM Failed to copy with forward slashes

C:\>copy "c:/temp\test.txt" "c:/temp/temp/"
        1 file(s) copied.

C:\>REM But forward slash works if last slash before file name is back slash


C:\>REM Rerun some past tests

C:\>type "c:/temp/test.txt"
The system cannot find the file specified.

C:\>REM Good - it still fails

C:\>dir "c:/temp/test.txt"
 Volume in drive C is OS
 Volume Serial Number is EE2C-5A11

 Directory of c:\temp

05/09/2012  09:58 PM                13 test.txt
               1 File(s)             13 bytes
               0 Dir(s)  337,001,615,360 bytes free

C:\>REM What is going on?! :( Why did that seem to work now?
C:\>REM More on that later.


C:\>REM Now test the new folder

C:\>type "c:/temp/temp/test.txt"
The system cannot find the file specified.

C:\>REM Forward slashes still fail with TYPE

C:\>type "c:/temp/temp\test.txt"
hello world

C:\>REM But forward slash still works as long as last slash is back slash

C:\>dir "c:/temp/temp/*"
 Volume in drive C is OS
 Volume Serial Number is EE2C-5A11

 Directory of c:\temp\temp

File Not Found

C:\>REM Again, forward slashes fail, but directory path is listed properly

C:\>dir "c:/temp/temp/"
 Volume in drive C is OS
 Volume Serial Number is EE2C-5A11

 Directory of c:\temp\temp

05/09/2012  09:58 PM    <DIR>          .
05/09/2012  09:58 PM    <DIR>          ..
05/09/2012  09:58 PM                13 test.txt
               1 File(s)             13 bytes
               2 Dir(s)  337,001,615,360 bytes free

C:\>REM And again it works if no file is specified

C:\>dir "c:/temp/temp\test.txt"
 Volume in drive C is OS
 Volume Serial Number is EE2C-5A11

 Directory of c:\temp\temp

05/09/2012  09:58 PM                13 test.txt
               1 File(s)             13 bytes
               0 Dir(s)  337,001,615,360 bytes free

C:\>REM Again forward slashes work as long as last slash is back slash

这是一个清楚地演示错误的案例.

c:\>dir /s /a-d temp
 Volume in drive C is OS
 Volume Serial Number is EE2C-5A11

 Directory of c:\temp

05/10/2012  08:01 AM                13 test.txt
               1 File(s)             13 bytes

 Directory of c:\temp\temp

05/10/2012  07:57 AM                10 test.txt
               1 File(s)             10 bytes

     Total Files Listed:
               2 File(s)             23 bytes
               0 Dir(s)  337,325,191,168 bytes free

c:\>REM Note the different file sizes found in each directory

c:\>dir "c:/temp/test.txt"
 Volume in drive C is OS
 Volume Serial Number is EE2C-5A11

 Directory of c:\temp

05/10/2012  07:57 AM                10 test.txt
               1 File(s)             10 bytes
               0 Dir(s)  337,325,191,168 bytes free

c:\>REM It is listing the wrong file!

人们可以争论Windows CMD是否"应该"支持正斜杠.但最后的结果是一个错误!即使使用正斜杠存在操作员错误,Windows也不应该提供该结果.

Answer 2

我不确定为什么“/”在 PS 中起作用。回到历史，DOS 是基于 UNIX 的，它是 UNIX 的一个小集合。在 UNIX 中，路径分隔符是“/”，而在 DOS 中，路径分隔符是“\”。我之前曾开发过一些 Windows 和 DOS 应用程序。为了转换一些 UNIX 模式（如命令或路径）并确保它们是有效的 DOS 命令或路径，我编写了一个小型转换器来将 '/' 转换为 '\'，如下所示：

string fileNameFromWeb;
...
string windowsFile = fileNameFromWeb.repleace("/", @"\");

您可以将此功能添加到应用程序中的宽容“/”中，以便访问 Windows 中的文件。我猜 PS 可能有这种类型转换器，允许命令或路径使用“/”或“\”，否则 Windows 将在文件名中采用“/”。