Computer file Created 2026-10-13 Updated 2026-10-31
An object whose contents and attributes can be accessed through operating system interfaces. Here an ordinary file means a byte sequence with file metadata, distinct from a file-system directory or a symbolic link. Its contents need not disappear when the creating operating-system process ends.
Names live in directory entries. Each ordinary directory entry associates a component name with an inode number; the corresponding inode describes the file and locates its contents. A name is therefore not stored as the identity of the inode, and hard links can give one inode several names.
To resolve
/var/mail/user, start from the root file-system directory's inode, read its directory entries and find var. Follow that entry's inode number to the var inode; read that file-system directory and find mail; repeat for user. The final inode supplies the file metadata and addresses needed to read the file data blocks. The intermediate file-system directories require search permission. This describes ordinary pathname traversal without a symbolic link or mount point changing the route. Symbolic link 2026-10-14
A separate file containing a path string to be interpreted during lookup. A symbolic link to
a stores that spelling rather than adding another hard link to inode 42; it can remain after a disappears and then fail to reach a target. It does not increase the target's hard link count. The diagrams below track only hard links and open references. [ref]https://pubs.opengroup.org/onlinepubs/009695299/functions/symlink.html. The Open Group, POSIX, symlink: storing the supplied path string
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