File Write Permission Rules

[Doug Gwyn]

In article <306 at wubios.wustl.edu> david at wubios.wustl.edu (David J. Camp) writes:
>My question is:  What is the (historical or otherwise) justification for
>this rule?  It seems wrong.  I would have required write permission to
>the file itself in order that it be removed.

I don't know what you think of when you say "file", so let's talk
about inodes instead.  One does NOT need to "write" (i.e. modify)
the contents of an inode in order to remove the link to it from
another (directory) inode, but one DOES need to be able to modify
the directory inode.

In other words, it works and makes sense, but you have to have the
right mental model of the UNIX hierarchical file system.