Allowed characters in filename

Question

Where can I find a list of allowed characters in filenames  depending on the operating system   e g  on Linux  the character   is allowed in filenames  but not on Windows

User · Answer

To be more precise about Mac OS X  now called MacOS    in the Finder is interpreted to   in the Unix file system    This was done for backward compatibility when Apple moved from Classic Mac OS    It is legitimate to use a   in a file name in the Finder  looking at the same file in the terminal it will show up with a      And it works the other way around too  you can t use a   in a file name with the terminal  but a   is OK and will show up as a   in the Finder    Some applications may be more restrictive and prohibit both characters to avoid confusion or because they kept logic from previous Classic Mac OS or for name compatibility between platforms

User · Answer

Here is the code to clean file name in python   import unicodedata  def clean name name  replace space with None               Remove invalid file name chars from the specified name       param name  the file name      param replace space with  if not none replace space with this string      return  a valid name for Win Mac Linux                ref  https   en wikipedia org wiki Filename       ref  https   stackoverflow com questions 4814040 allowed-characters-in-filename       No control chars  no                           lt    gt         remove control chars     name      join ch for ch in name if unicodedata category ch  0      C        cleaned name   re sub r            lt  gt         name      if replace space with is not None          return cleaned name replace      replace space with      return cleaned name

User · Answer

OK  so looking at Comparison of file systems if you only care about the main players file systems     Windows  FAT32  NTFS   Any Unicode except NUL                  lt    gt      Also  no space character at the start or end  and no period at the end  Mac HFS  HFS    Any valid Unicode except   or   Linux ext 2-4    Any byte except NUL or     so any byte except NUL                  lt    gt     and you can t have files folders call   or    and no control characters  of course

User · Answer

On Windows OS create a file and give it a invalid character like   in the filename  As a result you will get a popup with all the invalid characters in a filename

User · Answer

You should start with the Wikipedia Filename page  It has a decent-sized table  Comparison of filename limitations   listing the reserved characters for quite a lot of file systems   It also has a plethora of other information about each file system  including reserved file names such as CON under MS-DOS  I mention that only because I was bitten by that once when I shortened an include file from const h to con h and spent half an hour figuring out why the compiler hung   Turns out DOS ignored extensions for devices so that con h was exactly the same as con  the input console  meaning  of course  the compiler was waiting for me to type in the header file before it would continue

User · Answer

For  English locale  file names  this works nicely  I m using this for sanitizing uploaded file names  The file name is not meant to be linked to anything on disk  it s for when the file is being downloaded hence there are no path checks    file name   preg replace       x20-              lt  gt      g         client specified file name     Basically it strips all non-printable and reserved characters for Windows and other OSs  You can easily extend the pattern to support other locales and functionalities

[special-characters] Allowed characters in filename

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Examples related to filenames