Hard Links -Linux

[rajatkm93]

Can you please help me understand what's the logic behind hard link number shown in ls -l?

for example, I have /linuxgr8/home directory and for home directory it shows 3 hard link.
I have shared the tree structure of home directory.

 

[dos2unix]

From CoPilot -

1. What Is a Hard Link?
   • A hard link is a connection between two directory entries (or filenames) that point to the same inode (the fundamental data structure in a filesystem).
   • Unlike symbolic links (soft links), which point to the target file itself, hard links directly reference the inode.
   • When you create a hard link, it essentially creates an additional directory entry for the same file.
2. Understanding Inodes:
   • A Linux filesystem consists of two main components:
     • A pool of data blocks where actual file data is stored.
     • A database system (represented by inodes) that manages this data pool.
   • Each file has an associated inode that contains metadata (such as permissions, timestamps, and ownership).
   • Directories are essentially files that contain information about the inodes of their files and subdirectories.
3. Link Count:
   • The link count is the number of directory entries (or hard links) that point to a specific inode.
   • For example:
     • If a file has a link count of 1, it means there’s only one directory entry (hard link) pointing to that inode.
     • If a file has a link count greater than 1, it indicates multiple hard links to the same inode.
   • The link count is crucial, especially when dealing with hard links.
4. Example:
   • Consider the following directory structure:
     /
     ├── dir_1
     │ ├── file_1
     │ └── file_2
     └── dir_2
     ├── file_3
     └── hard_link_to_file_2
     
     
   • Here:
     • file_2 has a link count of 2 because it has two hard links: one in dir_1 and another in dir_2.
     • Both hard links point to the same inode (let’s say inode 17).
     • The link count for other files (like file_1 and file_3) is 1 because they have no hard links.
5. Viewing Link Count:
   • To see the link count of a file, use the ls -li command.
   • The third column in the output represents the link count.
   • For instance, if you run ln foo hlink2, the link count for foo will increase to 31.

 

[APTI]

From CoPilot -

1. What Is a Hard Link?
   • A hard link is a connection between two directory entries (or filenames) that point to the same inode (the fundamental data structure in a filesystem).
   • Unlike symbolic links (soft links), which point to the target file itself, hard links directly reference the inode.
   • When you create a hard link, it essentially creates an additional directory entry for the same file.
2. Understanding Inodes:
   • A Linux filesystem consists of two main components:
     • A pool of data blocks where actual file data is stored.
     • A database system (represented by inodes) that manages this data pool.
   • Each file has an associated inode that contains metadata (such as permissions, timestamps, and ownership).
   • Directories are essentially files that contain information about the inodes of their files and subdirectories.
3. Link Count:
   • The link count is the number of directory entries (or hard links) that point to a specific inode.
   • For example:
     • If a file has a link count of 1, it means there’s only one directory entry (hard link) pointing to that inode.
     • If a file has a link count greater than 1, it indicates multiple hard links to the same inode.
   • The link count is crucial, especially when dealing with hard links.
4. Example:
   • Consider the following directory structure:
     /
     ├── dir_1
     │ ├── file_1
     │ └── file_2
     └── dir_2
     ├── file_3
     └── hard_link_to_file_2
     
     
   • Here:
     • file_2 has a link count of 2 because it has two hard links: one in dir_1 and another in dir_2.
     • Both hard links point to the same inode (let’s say inode 17).
     • The link count for other files (like file_1 and file_3) is 1 because they have no hard links.
5. Viewing Link Count:
   • To see the link count of a file, use the ls -li command.
   • The third column in the output represents the link count.
   • For instance, if you run ln foo hlink2, the link count for foo will increase to 31.

stop it. you are hurting my brain.

 

[rajatkm93]

I have read that hard links cannot be created for directories, so how is it possible for the 'home' directory to show 3 hard links? And how I can see what r the files hard linked to this directory.

 

[CaffeineAddict]

I have read that hard links cannot be created for directories, so how is it possible for the 'home' directory to show 3 hard links? And how I can see what r the files hard linked to this directory.

Your screenshot shows directories (blue), these are not hard links.

In addition to the number indicating inode use count you also need to pay attention to filename color.
hard and soft link names in the terminal are pointing to another file name but you don't have this in your screenshot.

 

[osprey]

Perhaps this link will help:

What is the number between file permission and owner in ls -l command output?

The output of ls -l command yields the following result: What is the number field between file permission and owner? i.e. what are those 1, 1, 1, and 2? I checked the --help but that doesn't expla...

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