To maintain multiple of copy of a physical file . We use links to create virtual files instead physical files. There are two type of links:
Soft Links & Hard Links
Hard links can be created using command cp -l file1 file2 . "file2 here is the hard link. A hard link have same inode. If you delete a physical file of hard link . The content can still be viewed from the hard link.
Soft Links can be created using command cp -s file3 fil4 . "file4 here is the soft link. A Soft link don't have same inode. There always different. Once you delete a soft link physical file. The content is gone forever and can't be viewed even from a soft link.