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This article mainly introduces "what is the difference between chmod 755 and 4755 under CentOS". In daily operation, I believe that many people have doubts about the difference between chmod 755 and 4755 under CentOS. The editor consulted all kinds of materials and sorted out simple and easy-to-use methods of operation. I hope it will be helpful to answer the questions of "what is the difference between chmod 755 and 4755 under CentOS?" Next, please follow the editor to study!

Chmod is the command to set file permissions under Linux, and the following numbers indicate the permissions of different users or user groups.

There are usually three numbers:

The first number represents the permissions of the file owner

The second number represents the permissions of other users who belong to the same user group as the file owner

The third number represents the permissions of other user groups.

There are three kinds of permissions: read (read 4), write (write 2), and execute (xexecute 1). Taken together, there are readable executable (rx=5=4+1), readable and writeable (rw=6=4+2), readable and writable executable (rwx=7=4+2+1).

Therefore, chmod 755 sets the user's permissions to:

1. The file owner is readable, writable and executable

two。 Other users who belong to the same user group as the file owner can read and execute

3. Other user groups are readable and executable

Chmod 4755 differs from chmod 755 in that there is an extra bit at the beginning, which means that other users have the same permissions as the owner when executing the file.

For example, root users have created an Internet authentication program netlogin, and if other users want to use this program, it requires root users to run the chmod 755 netlogin command so that other users can also run netlogin.

However, when netlogin is executed, it may need to access some files that only root users have access to, so other users may not be able to access the Internet because of insufficient permissions when performing netlogin.

In this case, you can use chmod 4755 netlogin to set up other users who also have the authority of root users to execute netlogin, so as to surf the Internet smoothly.

At this point, the study on "what is the difference between chmod 755 and 4755 under CentOS" is over. I hope to be able to solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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