Special characters in a Windows filename

Question

Why can we not use any special characters (?, <..) in a Windows filename?

Because they have special meanings like input/output redirection, drive letter delimiter, 32k Unicode name support etc — Remus Rusanu, Oct 28 '10 at 05:36
similar [What characters are forbidden in Windows and Linux directory names?](https://stackoverflow.com/questions/1976007/what-characters-are-forbidden-in-windows-and-linux-directory-names) — milahu, Jan 03 '22 at 20:11
More specifically, *"[Reserved characters and words, In Windows](https://en.wikipedia.org/wiki/Filename#In_Windows)"* — Peter Mortensen, May 05 '23 at 21:40

score 5 · Answer 1 · edited May 05 '23 at 21:52

5

Fundamental rules for Universal Naming Convention (UNC), which enable applications to create and process valid names for files and directories, regardless of the file system:

The following reserved characters:

< (less than)

> (greater than)

: (colon)

" (double quote)

/ (forward slash)

\ (backslash)

| (vertical bar or pipe)

? (question mark)

* (asterisk)

Use any character in the current code page for a name, including Unicode characters and characters in the extended character set (128–255).

edited May 05 '23 at 21:52

Peter Mortensen

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answered Oct 28 '10 at 05:37

Sudantha

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This lists the characters (which is useful), but it doesn't answer the question (*** *** *** ***why*** *** *** ***). Whether that is a useful question is another matter. – Peter Mortensen May 05 '23 at 21:54

score 3 · Accepted Answer · edited May 05 '23 at 21:48

3

Because they have special meanings in the filesystem:

C:*.? - get all files with single letter extensions from the C drive

: \ * ? - all have special meanings

edited May 05 '23 at 21:48

Peter Mortensen

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answered Oct 28 '10 at 05:37

Riho

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score 0 · Answer 3 · edited May 05 '23 at 21:49

0

Since some characters are reserved characters in some operating systems, say ? is used as a wildcard, and / as a path name component separator.

edited May 05 '23 at 21:49

Peter Mortensen

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answered Oct 28 '10 at 05:41

Ads

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But this is specifically about Windows. – Peter Mortensen May 05 '23 at 21:50
Forward slash for Windows could need an explanation. – Peter Mortensen May 05 '23 at 21:52
That they are reserved characters doesn't answer the question (*** *** *** ***why*** *** *** ***). Whether that is a useful question is another matter. – Peter Mortensen May 05 '23 at 21:56

Special characters in a Windows filename

3 Answers3