In Ubuntu and other Unix-like operating systems (including all Linux distributions), the permission system is a very important part, which determines the access rights of users and programs to files and directories. A permission system helps protect the system from unauthorized access and modification.
In Ubuntu, every file and directory has the following three types of permissions:
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Read permission (r) : This permission allows the user to read the contents of a file or list the contents of a directory.
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Write permission (w) : This permission allows the user to modify the content of the file or create and delete files in the directory.
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Execute permission (x) : This permission allows the user to run the file as a program or enter a directory.
These permissions apply to the following three types of users:
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File Owner (u) : The user who created the file.
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The group to which the file belongs (g) : The user group to which the file owner belongs.
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Other users (o) : All other users except the file owner and the group the file belongs to.
You can use ls -lthe command to view the permissions of a file or directory. This will display a string like this: -rwxr-xr-x. This string is composed of ten characters. The first character indicates the file type ( -indicates ordinary files and dindicates directories), and the next nine characters are divided into three groups, each group of three characters indicates the file owner and the group to which the file belongs. and other user permissions.
You can use chmodthe command to change the permissions of a file or directory. For example, if you want to add execute permission to the owner of the file, you can chmod u+x 文件名run
The owner of files and directories can chownbe changed using the command, eg chown 用户名:组名 文件名.
Overall, understanding and managing Ubuntu permissions is very important to keep your system secure and prevent unauthorized users or programs from accessing or modifying your files. However, you also need to be cautious about changing permissions. The wrong permission setting may reduce the security of the system or prevent you and your programs from accessing required files.