Linux soft links and hard links: interpretation of principles and characteristics

Linux soft links and hard links: interpretation of principles and characteristics

In Linux systems, soft links and hard links are common concepts in file systems. They can Let us manage files and directories more flexibly. In this article, we will delve into the principles and characteristics of soft links and hard links to help readers better understand their differences and uses.

1. The Concept of Soft Links and Hard Links

Soft link (Symbolic Link), also known as symbolic link, is a special type of file, similar to shortcuts in Windows systems. It only contains the path to the target file or directory. In other words, a soft link is just a pointer to another file. When you access a soft link, you actually access the target file it points to.

Hard Link is another form of link in the file system. It is actually another copy of the target file, but the system will allocate the same index node (inode) to them, so that They share the same data block. Therefore, whether it is the original file or the hard link file, the file content is exactly the same.

2. The difference between soft links and hard links

1. File type: Soft links and hard links have different forms of expression in the file system. A soft link is a new file. It only contains the path information of the target file; while a hard link is another copy of the original file, and their inodes in the file system are the same.
2. Modify behavior: When the original file is deleted, the target file pointed to by the soft link will no longer exist, but the hard link will not be affected because the hard link and the original file share the same inode. When the original file is deleted, the same data can still be accessed by the hard link.
3. Cross-file system: Soft links can point to target files in other file systems, while hard links can only exist in the same file system.
4. Permissions of soft links: Soft links have their own permission settings, while hard links have the same permissions as the original file.
5. Target file path: Soft links are allowed to point to non-existent target files or directories, while hard links must point to files that already exist.

3. Application scenarios of soft links and hard links

1. Soft links are often used for cross-file system links to facilitate users to create convenient access methods between different locations. , for example, create a soft link to a frequently accessed file to the desktop.
2. Hard links are suitable for scenarios where the same data needs to be accessed in different locations at the same time. It can save disk space and improve file access efficiency in high-load environments.
3. Soft links are also often used to link programs that depend on libraries, so that the program can access the latest version of the library file based on the soft link.

4. Summary

Soft links and hard links are commonly used file link forms in Linux systems. They each have different characteristics and application scenarios. A soft link is a virtual link pointing to a target file or directory, suitable for link scenarios that need to span different file systems; a hard link is another copy of the target file, which is exactly the same in file content, and is suitable for links that need to share the same data. Scenes. By deeply understanding the principles and characteristics of soft links and hard links, we can better use them to manage files and directories and improve the flexibility and efficiency of the system.

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