Shell Programming and Scripting

ln -f <src> <dst>
chmod 744 <yourfile>

#Create the hard link
ln -f /tmp/file /var/file

#Give the permission
chmod 755 /var/file

A hard link can point only to a file and not to a directory, and only to a file existing on the same file system where the link itself is. 
A symbolic link, in contrast, can point to a file or a directory and can span across file systems. 
Furthermore, you cannot create a hard link for a non-existent file, whereas you can create a symbolic link for it. 
Links can be removed with the same rm command that is used to remove files.

man ln

you can control the permission by using "chmod" command , to create a soft link use "ln -s" command

Creating Hard and Symbolic Links
To create a symbolic link or a hard link, you use the same command name, In, which has the following syntax:

In [-fns] <source> [<target>]


Hard link is the default output of the ln command-that is, if you issue the ln command without the - s option, a hard link will be created.
 

In this command, <source> is the original file and <target> is the link that will be created and linked to the <source>. The options for the command are listed here:

-f (force). Link the file without questioning the user.

-n. If the <target> is an existing file, do not overwrite the content of the file. The -f option overrides this option.

-s. Create a symbolic link. The default is a hard link.

The hard links and symbolic links are compared in Table 4-2 

Table 4-2: Comparison of hard and soft links  Characteristic
 Hard Link
 Soft Link
 
Existence of original file
 You cannot create a hard link to a file that does not exist.
 You can create a symbolic link to a file that does not exist.
 
File systems
 A hard link cannot span file systems-that is, the link and the file it points to have to be in the same file system.
 A soft link can span file systems.
 
Kind of original file
 A hard link can only point to a file that is not a directory.
 A soft link can point to a file or a directory.
 
I-node
 A hard link has the same inode number as the file it points to.
 A soft link has a different inode from the file it points to.