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How to modify file permissions using chmod command in Linux? I believe that many inexperienced people are helpless about this. For this reason, this article summarizes the causes and solutions of the problem. Through this article, I hope you can solve this problem.

Use the following command:

chmod 777 File or directory

Example: chmod 777 /etc/squid After running the command, the squid folder (directory) permissions are modified to 777 (readable, writable and executable).

If it is an Ubuntu system, you may need to add sudo to execute:

sudo chmod 777 /etc/squid

At the beginning of the story, there will be a suspense.

In the series of cold jokes that only programmers can understand, there is a classic paragraph:

Please describe our FL in the most concise language.

754。

What does 754 mean? What does 754 mean? What does 754 mean?

The chmod command is described below.

Linux system, each user's role and permissions are very detailed division is also very strict, each file (directory) has access permissions, using this mechanism to determine a certain user through a certain way to file (directory) read, write, execute and other operations.

There are three different types of users who manipulate files or directories: file owners, group users, and other users. The highest digit indicates the permission value of the file owner, the middle digit indicates the permission value of the group user, and the lowest digit indicates the permission value of other users. Therefore, in chmod 777, the three numbers 7 correspond to the above three users respectively, and the permission value is 7.

File or directory permissions are divided into three types: read-only, write-only, executable.

Permission permission value binary specific role r400000100read, read. The current user can read file contents and browse directories. W20000010 write, write. The current user can add or modify file content, and the current user can delete, move directories or files in directories. x10000001 execute, execute. The current user can execute files and the current user can enter directories.

According to the table above, permission combinations are the sum of the corresponding permission values, as follows:

7 = 4 + 2 + 1 Read and write operation permission

5 = 4 + 1 read and run permissions

4 = 4 Read Only Permission

So, you know what chmod 754 filename means.

This command gives the filename file owner read and write permissions, group users read and run permissions, and other users read permissions.

More official, detailed explanations can be viewed using the following command:

chmod --help or man chmod

Linux is a free-to-use and freely distributed UNIX-like operating system, is a POSIX-based multi-user, multitasking, multi-threaded and multi-CPU operating system, using Linux to run major Unix tools, applications and network protocols.

After reading the above, do you know how to use chmod command to modify file permissions in Linux? If you still want to learn more skills or want to know more related content, welcome to pay attention to the industry information channel, thank you for reading!

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