为什么测试特殊符号

Characters are disallowed because they have special meaning on the Command Prompt.

" (double quote)... Denotes the start and end of a quoted filename. Without this, you couldn't have spaces

* (asterisk)... Denotes a wildcard. You might see in Windows search the ability to search for something.

/ (forward slash)... Denotes a command option. If you named a file this and it was used on the command line, it couldn't tell if you were wanting a file named "Subject1/Subject2" or just "Subject1" with the special option called "Subject2".

: (colon)... Denotes a drive (i.e. C:)

> (greater than)... Denotes output redirection. You could run some program>some file and it would mean "Run 'some program' and put the output in the file 'somefile'". The < does the same with input.
< (less than)... Same as > but with input instead of output.

? (question mark)... Also a wildcard character like * is

\ (blackslash)... Separates a directory. foo\bar indicates that bar is in the directory foo.

| (bar)… Command piping. Foo | bar will take the output from foo and use it as the input to bar.

If filenames were allowed with these characters, the command prompt would get confused on if you meant them as part of the filename or part of the command.