Permissions

Understanding Users and Groups A user is an individual entity that uses the system. Each user is assigned a unique User ID (UID), where UID 0 generally represents the root user, while normal users are assigned UIDs greater than 1000. Each user has a home directory where they can store personal files and configurations, and they can set their preferred shell, environment variables, and access permissions individually. In contrast, a group is a collection of users that can be managed as a unit, allowing permissions to be assigned to files or directories at the group level. Users can belong to multiple groups simultaneously, typically having a primary group assigned during account creation and additional supplementary groups added as needed. Groups also have a unique Group ID (GID) like users. ...

Understanding Linux Permissions Linux, adhering to UNIX heritage, possesses a robust file permission system. Every file and directory can have specific read, write, and execute permissions for its owner, group, and other users. This mechanism facilitates security and resource sharing in multi-user systems. Composition of Basic Permissions Linux permissions consist of three basic elements: read (r), write (w), and execute (x). These permissions can be set independently for the owner, group, and others. Notations like -rwxr-xr– seen while listing files represent combinations of such permissions. ...