The Below article give you a picture of what are Hard links.
A hard link is essentially a label or name assigned to a file. Conventionally, we think of a file as consisting of a set of information that has a single name. However, it is possible to create a number of different names that all refer to the same contents. Commands executed upon any of these different names will then operate upon the same file contents.
To make a hard link to an existing file, enter:
ln thisfile sameasthisfile
Replace thisfile with the original filename, and sameasthisfile with the additional name you like to use to refer to the original file.
This will create a new item in your working directory, sameasthisfile, which is linked to the contents of thisfile. The new link will show up along with the rest of your file names when you list them using the ls command. This new link is not a separate copy of the old file, but rather a different name for exactly the same file contents as the old file. Consequently, any changes you make to thisfile will be visible in sameasthisfile file.
You can use the standard Unix rm command to delete a link. After a link has been removed, the file contents will still exist as long as there is one name referencing the file. Thus, if you use the rm command on a file name, and a separate link exists to the same file contents, you have not really deleted the file; you can still access it through the other link. Consequently, hard links can make it difficult to keep track of files. Furthermore, hard links cannot refer to files located on different computers linked by NFS, nor can they refer to directories. For all of these reasons, you should consider using a symbolic link, also known as a soft link, instead of a hard link.
below link has good information.
http://superuser.com/questions/12972/how-can-you-see-the-actual-hard-link-by-ls
good article on hardlink and soft link.
http://linuxgazette.net/105/pitcher.html
