We've mentioned the term link when referring to the relationship between
directory entries and inodes. There are actually two kinds of links available
on Linux. The kind we've discussed so far are called hard links.
A given inode can have any number of hard links, and the inode will persist on
the filesystem until all the hard links disappear. New hard links can be
created using the ln command:
$ cd /tmp
$ touch firstlink
$ ln firstlink secondlink
$ ls -i firstlink secondlink
15782 firstlink 15782 secondlink