> ls -l
total 4
-rw-r-r-    1 erik     erik            1 Feb 16 02:07 test

> ln test test2
> ls -l
total 8
-rw-r-r-    2 erik     erik            1 Feb 16 02:07 test
-rw-r-r-    2 erik     erik            1 Feb 16 02:07 test2

Notice field 2 changed from 1 to 2 indicating that a hard link has been created. There are now 2 filenames pointing to the same data.

To list all hardlinked files in the current directory:

> find . ! -type d -links +1 -ls | sort -n
 18587    4 -rw-r-r-   2 erik     erik            1 Feb 16 02:07 ./test
 18587    4 -rw-r-r-   2 erik     erik            1 Feb 16 02:07 ./test2

Note: Use: ls -i to also list directories.

To find all hardlink to the same inode:

> find / -xdev -inum 18587
/home/erik/test/test
/home/erik/test/test2

Note: Hardlinks have to be located on the same file system, use df . to determine the current filesystem.