Hardlinks (was: Re: Does the bash bug have a zsh counterpart?)

[Dirk Heinrichs <dhs@xxxxxxxxxxxxx>]

Am 25.09.2014 um 18:53 schrieb William G. Scott:

(About 10 years ago I found a hard link to a then nonexistent ksh behaved properly whereas a symbolic link for whatever reason didn’t).

A hardlink is nothing more than another name for the same file. When ksh was deleted, the system has just deleted that one NAME of the file, but it stayed there under the other name (sh). That's the reason why you can't create hardlinks across filesystem borders. BTW: You can identify hardlinked files by looking at

1. The link count:
   % touch foo
   % ln foo bar
   % ll foo bar
   -rw-r--r-- 2 someuser users 0 Sep 26 07:36 bar
   -rw-r--r-- 2 someuser users 0 Sep 26 07:36 foo
   % ln bar baz
   % ll foo bar baz
   -rw-r--r-- 3 someuser users 0 Sep 26 07:36 bar
   -rw-r--r-- 3 someuser users 0 Sep 26 07:36 baz
   -rw-r--r-- 3 someuser users 0 Sep 26 07:36 foo
2. The inode number
   % ll -i foo bar baz
   22 -rw-r--r-- 3 someuser users 0 Sep 26 07:36 bar
   22 -rw-r--r-- 3 someuser users 0 Sep 26 07:36 baz
   22 -rw-r--r-- 3 someuser users 0 Sep 26 07:36 foo
   

The link count tells you whether a file has multiple names, while the inode number tells you which names a file has.

A symlink, OTOH, is just a NEW (special) file, pointing to another file which may exist or not.

HTH...

    Dirk

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Dirk Heinrichs, Senior Systems Engineer, Engineering Solutions
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