Why does dir *.txt return *.txtf also?

不羁岁月 提交于 2019-12-30 12:12:05

问题


No doubt this has been answered already :/ I'm not certain how to word this. I just want the file one.txt to return by what I thought would be dir *.txt

Here are some examples to show that it doesn't behave like I had thought.

dir *.txt

one.txt
one.txtf

dir *txt

one.txt
one.txtf

dir *txtf

one.txtf

dir *tx?

one.txt
one.txtf

dir *.???

one.txt
one.txtf

dir one.???

one.txt

dir *"."???

one.txt
one.txtf

回答1:


EDITED

In short - by definition the DIR command works as you're implying so it's one of those "by design" things.

From Microsoft on the DIR command directly. This explanation is a bit more winded than the below from the .NET framework.

From MSDN on the .NET Framework Implementation

When using the asterisk wildcard character in a searchPattern, such as ".txt", the matching behavior when the extension is exactly three characters long is different than when the extension is more or less than three characters long. A searchPattern with a file extension of exactly three characters returns files having an extension of three or more characters, where the first three characters match the file extension specified in the searchPattern. A searchPattern with a file extension of one, two, or more than three characters returns only files having extensions of exactly that length that match the file extension specified in the searchPattern. When using the question mark wildcard character, this method returns only files that match the specified file extension. For example, given two files, "file1.txt" and "file1.txtother", in a directory, a search pattern of "file?.txt" returns just the first file, while a search pattern of "file.txt" returns both files.



来源:https://stackoverflow.com/questions/11424577/why-does-dir-txt-return-txtf-also

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