Users, Groups, and Permissions

This beginner course builds a practical model of Linux identity and file access. Across six guided labs, you will inspect users and groups, distinguish ownership from permissions, read symbolic and octal modes, elevate privileges carefully, and control the defaults applied to new files.

An independent final challenge brings the pieces together in a shared workspace. You will verify a prepared developer account, create /srv/dev, assign its group ownership, and restrict access to the owner and development team.

What You Will Learn

• Read account fields in /etc/passwd and inspect user and group membership with id
• Identify file owner and group columns with ls -l, then change them with chown and chgrp
• Decode file type and user, group, and other rwx permission blocks
• Convert permission sets between symbolic form and octal values such as 644, 600, and 770
• Adjust access with symbolic and octal chmod operations
• Use sudo for one privileged command, enter a root shell with sudo -i, and return with exit
• Explain how umask affects new files and compare results from 002 and 077
• Configure and verify a group-owned /srv/dev directory with mode 770

Who This Course Is For

This course is for Linux beginners and aspiring system or DevOps administrators who want hands-on foundations in account identity, ownership, permissions, and controlled privilege elevation.

Prerequisites: Basic terminal navigation, file creation, and command execution; no prior user-administration experience is required.

Learning environment: A provided Ubuntu-based LabEx terminal with a regular labex account, passwordless lab access to sudo, prepared users and groups, and files for permission exercises.

Frequently Asked Questions

How much of the course is guided?

The first six labs provide step-by-step practice. The seventh item is a final challenge where you apply id, sudo, directory creation, group ownership, and octal permissions with less guidance.

Will I create or delete Linux users and groups?

No. You inspect existing account records and group memberships. The final challenge uses the prepared user alice and group developers; commands such as useradd, groupadd, and account deletion are outside this course.

Does the shared-workspace challenge configure SGID?

No. It assigns the developers group to /srv/dev and sets mode 770. SGID and automatic group inheritance for newly created files are not implemented in this challenge.

Will I work as root throughout the labs?

No. You first see a normal-user permission denial, use sudo for a single command, briefly enter a root shell to understand the distinction, and then exit back to the labex account.