How To Understand Difference Between Symbolic Link And Hard Link.

File systems provide various ways to create references to files, with two of the most common being symbolic links and hard links. While both serve the fundamental purpose of referencing a file, there are significant differences between them, both in terms of how they are created and their behavior within the file system.

1. Definition and Basic Characteristics

Symbolic Link (symlink)

A symbolic link is a special type of file that serves as a reference to another file or directory. The symlink contains the path to the target file.

Hard Link

A hard link is an additional reference to an existing inode of a file. Each hard link represents a separate directory entry with its own filename, but all hard links to the same file share the same inode.

2. Nature and Structure of Links

Symbolic Link (symlink)

The symlink is a separate file with its own inode. If the target file is deleted or moved, the symlink becomes broken.

Hard Link

All hard links to a file share the same inode. There is no concept of a “target” file. Deleting or moving the original file doesn’t affect hard links because they all reference the same data on disk.

3. Compatibility Across File Systems

Symbolic Link (symlink)

Can span different file systems because it references the target by path.

Hard Link

Usually restricted to the same file system because all links point to the same inode.

4. Size and Physical Structure

Symbolic Link (symlink)

Small in size, typically just the size of the path.

Hard Link

Same size as the original file since all links point to the same data blocks.

5. Updates and Modifications

Symbolic Link (symlink)

Changes to the target file’s name or location don’t automatically update the symlink. The symlink might become broken if the target is deleted or moved.

Hard Link

Any change to the file through one hard link is reflected in all hard links since they all point to the same inode.

6. Creation of Links

Symbolic Link (symlink)

Created using the ln -s command.

Hard Link

Created using the ln command without the -s option.

Conclusion

In essence, symbolic links and hard links fulfill the same fundamental purpose but have different characteristics and behaviors in file systems. The choice between them depends on the specific requirements of the user and the usage conditions of the files. Proper usage and understanding of these differences can contribute to efficient file and directory management in operating systems.