Linux File Systems and Permissions Questions

Comprehensive coverage of Linux file system internals, the standard filesystem hierarchy, practical administration tasks, and the permission and access control model. Candidates should understand the purpose of directories such as /etc, /var, /usr, /home, /tmp, and /opt; how files and directories are represented by inodes and directory structures; the role of file descriptors; and how mounts and different filesystem types and mount options affect behavior and available features. Practical skills include creating deleting moving copying and renaming files and directories; managing symbolic links and hard links; mounting and unmounting filesystems and configuring persistent mounts; checking disk usage and block device information; and basic backup restore and integrity check workflows. Permission and access control topics include user group and other classes; read write and execute bits and octal notation; special permission bits such as set user id set group id and the sticky bit; default creation mask and umask; ownership management with chown and chgrp; permission changes with chmod; and the use of access control lists for fine grained permissions when supported. The topic also encompasses user and group management as it relates to file ownership and access control including adding and removing users and groups managing group membership sudo configuration and the role of system account files such as /etc/passwd /etc/shadow and /etc/group. Interview assessment typically focuses on practical commands and procedures diagnosing permission related failures reasoning about secure defaults and trade offs between security and usability and designing safe backup mount and maintenance strategies.