undefined | Better HN

0 pointsbobbylarrybobby4y ago0 comments

I was under the impression that unless a file contains some other metadata (most don't), that the extension is the way the OS chooses which app to use to open it.

0 comments

boomboomsubban4y ago

Unix-based has almost always used internal metadata, and the "dot" is just another character. I thought Windows was unique in relying on the suffixes, but Wikipedia suggests MacOS inherited some form from NextSTEP.

spijdar4y ago

"Unix" OSes in my experience simply don't (universally) have a way to "open this file in the correct application". It's a foreign concept. Files are just sequences of bytes, and file paths are just addresses to those bytes. The file extensions are, then, purely for the sake of the user, as there is no (standard) way to store file metadata. There are specific filesystems with these metadata extensions, but otherwise, you need to resort to commands like file and libmagic for heuristics on determining file-type.

Or just use the file suffix, which is AFAIK what all the mainstream Linux desktop environments do, through Freedesktop's MIME implementation. I don't know if it supports using metadata or file magics instead, but a quick glance shows almost every MIME definition uses file globbing.

You can check this in the files located at "/usr/share/mime/application" and "/usr/share/mime/packages" on most distros. Most (all?) definitions use a "glob pattern" to match files.

ziml774y ago

I wonder if filesystems should be designed to store the MIME type alongside the file. Web browsers get MIME types alongside the data (and they do make use of that info).

j / k navigate · click thread line to collapse