In-depth understanding of the difference between soft links and hard links in Linux

Soft links and hard links in Linux are two common link methods. They have some differences in use. This article will explore in depth the characteristics and differences of these two links. .

1. Soft link

Soft link (symbolic link), also known as symbolic link, is a link pointing to a file or directory, similar to a shortcut under Windows system. A soft link is actually a special file that contains the path information of the original file. When we open a soft link, we are actually accessing the linked object.

1. Create soft link: Under Linux system, you can use the ln -s command to create a soft link. For example, to create a soft link link.txt pointing to the file file.txt, you can use the following command:

   ln -s /path/to/file.txt /path/to/link.txt

2. Features:

   • Soft links have their own The inode number, the file size is a few bytes, and it takes up very little space.
   • When the original file is deleted, the soft link still exists, but the file pointed to will become invalid.
   • Soft links can link files or directories, and cross-file system links can also be implemented.
   • You can create soft links pointing to directories to achieve cross-directory access.

3. Usage scenarios:

   • Share the same file in different directories
   • Maintain multiple versions of the program
   • Link dynamic library

2. Hard link

Hard link (hard link) refers to multiple files sharing the same index node (inode). They actually Points to the same file data block. Hard links can only be created within the same file system and cannot be created across file systems.

1. Create a hard link: Under Linux system, use the ln command to create a hard link. For example, to create a hard link to file.txt as link.txt, you can use the following command:

   ln /path/to/file.txt /path/to/link.txt

2. Features:

   • Hard link with original file Share the same inode and data block, so the file size and inode number are the same.
   • Deleting the original file will not affect the access of the hard link, because the hard link itself is a reference to the data block, and the data block will only be released after all links are deleted.
   • Cannot create a hard link for a directory because the hard link points to the inode instead of the file name.

3. Usage scenario:

   • Write an automatic backup script
   • Ensure that important files are not accidentally deleted
   • Save space, multiple files actually share the same data block

##3. Comparison of soft links and hard links

1. Difference:
   Soft links and hard links are different in implementation. A soft link is an independent file, while a hard link is multiple files sharing the same index node.
   • Soft links can point to directories, but hard links cannot.
2. Common points:
   Both soft links and hard links can be used to create links to files or directories to facilitate multi-file operations. .

Conclusion:

Soft links and hard links each have their own characteristics and applicable scenarios. Choosing the appropriate link method according to your needs can better manage and Organize files. Understanding the differences between soft links and hard links will help you make better use of the file management functions of the Linux system and improve work efficiency.

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