The function and application of i-node number in Linux system

Title: The function and application of i-node number in Linux system

In Linux system, i-node number (inode number) is a very important concept. It is used to identify files and directories in a file system. Each file or directory has a unique i-node number. Through the i-node number, you can quickly locate and access the metadata information of the file, including the file's permissions, owner, size, creation time, etc., without having to rely on the file name to find it. .

The function and application of i node numbers play a vital role in file system management and data recovery. This article will introduce the concept, function and specific application of i-node numbers in detail, and explain it with code examples.

1. The concept and function of i-node number

In the Linux file system, each file or directory corresponds to an i-node (inode), and the i-node stores the elements of the file or directory. Data information, including file type, size, owner, permissions, number of links, location of data blocks, etc. The i-node number is used to uniquely identify each i-node. Through the i-node number, the corresponding i-node can be quickly accessed to obtain detailed information of the file.

The main functions of the i node number are as follows:

1. Identify files: The i node number can uniquely identify a file or directory and is not affected by the file name.
2. Efficient access: The i-node number can quickly locate the metadata information of the file and improve the access efficiency of the file system.
3. Data recovery: When the file system is damaged or the file is lost, you can try to recover the file data through the i-node number.

2. Specific application example of i-node number

1. View the i-node number of a file

In Linux system, you can use the command ls -i to display the i-node number of the file. For example, for the file "example.txt", you can view its i-node number through the following command:

$ ls -i example.txt

2. Access the file through the i-node number

You can use The stat command obtains detailed information about the file through the i-node number. For example, through a file with i-node number 123456, you can use the following command to obtain file information:

$ stat -c "%n %i %s %u %g %a %A" $(find / -inum 123456)

This command will display the file path, i-node number, size, owner, group, permissions and finally Modification time and other information.

3. Recover files using i-node numbers

When the file system is damaged or files are lost, you can try to recover file data through i-node numbers. First, you need to find the known i-node number, and then use tools such as debugfs or extundelete to find the file data and restore it.

In addition to the above examples, the i-node number can also play an important role in file system management, data backup, etc., and is an indispensable concept in the Linux system.

Summary

Through the introduction of this article, readers can have an in-depth understanding of the functions and applications of i-node numbers in Linux systems. As the core concept of file system management, i-node number can help users access files efficiently, locate metadata information, and provide important support during data recovery. Through specific code examples, readers can more intuitively understand the use of i-node numbers and further improve their understanding and application capabilities of the Linux file system.

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