Learn Linux: Ubuntu Setup, Commands, Permissions and SSH
YOUR LEARNING PATH
Prepare a virtual environment you can restore, then work through files, command output, permissions and processes. The aim is to understand what a command changed and where to look when the result differs from your expectation.
Who is this path for?
First-time Linux users and learners preparing for security labs who want a stronger command-line foundation
Before you begin
Prepare a PC that can run a virtual machine and follow the Ubuntu setup lesson. Take a snapshot before experiments and keep important personal files outside the lab.
What you will practice
- Navigate directories and find information with grep and find.
- Read rwx permissions and ownership, and distinguish execution privileges.
- Observe the system through processes, logs, SSH and bash scripts.
STEP BY STEP
Your suggested lesson order
Build a Linux environment you can restore
- 016 Understanding Virtualization — Building a Computer Inside a ComputerExplain what a virtual machine (VM) and a hypervisor are
- 017 Installing Ubuntu and Snapshots — Moving Into the Lab and Setting Save PointsExplain what an ISO file and LTS are
- 018 Linux Basic Commands 1 — Finding Your Way in the Black WindowExplain that the Linux filesystem is a single tree rooted at /
Learn commands and permissions
- 019 Linux Basic Commands 2 — Three Pipes for Steering OutputExplain the three standard streams (stdin/stdout/stderr) along with their numbers
- 020 Searching (grep/find) — Finding Two Needles in a HaystackExplain the difference in roles between grep (content search) and find (name/condition search)
- 021 Package Management — apt, Linux's App StoreExplain the three concepts of package, repository, and dependency
- 022 Editors — Surviving the Terminal with nano and vimExplain why terminal editors are needed, and why cat or > isn’t enough
- 023 Permissions 1 — rwx, Rules Carved Into FilesInterpret a string like -rwxr-xr-- at the front of ls -l output, class by class
- 024 Permissions 2 — Ownership and sudo: How to Wield PowerExplain what root (UID 0) is and why it bypasses permission checks
- 025 User Management Lab — Crossing the Boundary Between Authentication and AuthorizationExplain the difference between authentication and authorization with examples
Connect automation with security foundations
- 026 Process Management — List Them, Find Them, Signal ThemView the list of running processes and find each one’s PID (number) and PPID (parent’s number)
- 027 Exploring the Directory Structure — Putting the Linux Map in Your HandsExplain the roles of Linux’s top-level folders (/etc, /var, /bin, etc.)
- 028 bash Scripts and cron — Hand Your Typed Commands Over to an Alarm ClockCreate a shell script that gathers several commands in a file and runs them at once
- 029 SSH Remote Access — Opening the Encrypted Front GateExplain what SSH is and which problem of plaintext communication it solves
- 030 ★ Project: Monitoring Automation — Building a Watcher That Works AloneExplain what monitoring is and why "records" become the baseline of normal
- 106 Linux Permissions Deep Dive — setuid, setgid, sticky bitExplain how setuid, setgid, and the sticky bit each work in one sentence
- 107 Exploring Linux Logs — /var/logState the roles of the main files in /var/log (auth.log, syslog, kern.log, wtmp, etc.)
- 108 Environment Variables and PATH InjectionExplain what environment variables are, and read and write them with export and $VARIABLE
- 109 Symbolic Links and Hard Links — Another Name for a FileExplain the structure in which a file's substance (inode) and its name are separated
- 110 Project: "The Gaps in Linux's Permission Model" Reference Document — Reviewing Through an Attacker's EyesOrganize 4 types of Linux privilege-bypass points into the 4-part structure "conditions / discovery / exploita…
Before you move on
In a snapshot-backed lab, find files, inspect permissions and list processes without following every example verbatim. For automation, record what happens with missing input or insufficient permissions as well as the successful case.
Check each lesson’s setup and completion criteria. If you already know a section, start with the lessons you need.