find: Hard Links
2.3.2 Hard Links
----------------
Hard links allow more than one name to refer to the same file on a file
system, i.e., to the same inode. To find all the names which refer to
the same file as NAME, use '-samefile NAME'.
-- Test: -samefile NAME
True if the file is a hard link to the same inode as NAME. This
implies that NAME and the file reside on the same file system,
i.e., they have the same device number.
Unless the '-L' option is also given to follow symbolic links, one
may confine the search to one file system by using the '-xdev'
option. This is useful because hard links cannot point outside a
single file system, so this can cut down on needless searching.
If the '-L' option is in effect, then dereferencing of symbolic
links applies both to the NAME argument of the '-samefile' primary
and to each file examined during the traversal of the directory
hierarchy. Therefore, 'find -L -samefile NAME' will find both hard
links and symbolic links pointing to the file referenced by NAME.
'find' also allows searching for files by inode number.
This can occasionally be useful in diagnosing problems with file
systems; for example, 'fsck' and 'lsof' tend to print inode numbers.
Inode numbers also occasionally turn up in log messages for some types
of software.
You can learn a file's inode number and the number of links to it by
running 'ls -li', 'stat' or 'find -ls'.
You can search for hard links to inode number NUM by using '-inum
NUM'. If there are any file system mount points below the directory
where you are starting the search, use the '-xdev' option unless you are
also using the '-L' option. Using '-xdev' saves needless searching,
since hard links to a file must be on the same file system. ⇒
Filesystems.
-- Test: -inum n
True if the file has inode number N. The '+' and '-' qualifiers
also work, though these are rarely useful.
Please note that the '-inum' primary simply compares the inode
number against the given N. This means that a search for a certain
inode number in several file systems may return several files with
that inode number, but as each file system has its own device
number, those files are not necessarily hard links to the same
file.
Therefore, it is much of the time easier to use '-samefile' rather
than this option.
'find' also allows searching for files that have a certain number of
links, with '-links'.
A directory normally has at least two hard links: the entry named in
its parent directory, and the '.' entry inside of the directory. If a
directory has subdirectories, each of those also has a hard link called
'..' to its parent directory.
The '.' and '..' directory entries are not normally searched unless
they are mentioned on the 'find' command line.
-- Test: -links n
File has N hard links.
-- Test: -links +n
File has more than N hard links.
-- Test: -links -n
File has fewer than N hard links.
Info Catalog
find: Symbolic Links
find: Links