Contents
Roadmap info from roadmap website
Linux: Permissions Under User Management
Linux, like all Unix-like systems, is a multi-user system, meaning it can be used by multiple users at one time. As such, it has a comprehensive system for managing permissions for these users. These Linux permissions dictate who can access, modify, and execute files and directories.
Permissions are categorized into three types:
- Read permission: Users with read permissions can view the contents of the file.
- Write permission: Users with write permissions can modify the contents of the file or directory.
- Execute permission: Users with execute permissions can run a file or traverse a directory.
These permissions can be set for three kinds of entities:
- User: The owner of the file or directory.
- Group: The user group that owns the file or directory.
- Others: Other users who are neither the owner of the file, nor belong to the group that owns the file.
To set these permissions, Linux uses a system of permission bits. This information can be viewed and manipulated using commands such as chmod, chown, and chgrp.
chmod 755 my_file
chown new_owner my_file
chgrp new_group my_file
In the example above, chmod 755 my_file sets permissions so that the user can read, write, and execute (7), while the group and others can read and execute (5). The chown and chgrp commands change the owner and group of my_file, respectively.