Hi David,
On Mon, Feb 9, 2009 at 2:54 PM, David Ryder wrote:
> Hi,
> I have not been able to find an explanation why:
> 1. hard links are not allowed for directories, and
At a file system level, a directory contains a list of inodes, which
then point to file data.
A hardlink is a duplicate inode, which points to the same file data as
another inode.
Directories are not inodes, so can't be 'hard linked'. [1]
> 2. soft links to directories are not automatically removed if the target
> is deleted. The link to the directory remains and is obviously useless
> so why doesn't 'nix delete them too?
Um.. good question. Same goes for softlinks to files.
The underlying reason is that a softlink is a 'reference in a
directory' to another 'directory entry'. When you delete a file or
directory, the filesystem has no 'local' record of who else may be
pointing to (referencing it). So, it stops there, rather than scanning
the entire filesystem when you delete each file to look for possible
floating softlinks.
> Many thanks to anybody who can tell me why or point me to unix
> documentation explaining why - it is very elusive to find, methinks.
The following might be useful.. see "The File System" section
http://tldp.org/LDP/tlk/tlk.html
Notes:
[1] Oddly enough, I did actually manage to create what looked like a
hard link to a directory in SunOS as the result of a 'fsck'.
Unfortunately 'rm' didn't work. The OS error was something along the
lines of.. "you can't remove this as hard linked directories don't
exist'. I ended up just moving it out of the way...
> David
Paul
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