Can You Pass the Week 1 Linux Quiz? — Boot, Permissions, awk & Bash | Zero to LLMOps (Day 7)

Day 7 of a free 180-day DevOps course. There is no new material today — because today is the review day that decides whether the last six days were worth anything. Recognizing a command when you read it is not the same as retrieving it cold under pressure during an incident. Today is 100% active recall and hands-on terminal verification: a cumulative quiz across Days 1–6, closed-book weakest lab redo, project verification & backup, and the 1-3-7-21 spaced repetition ritual. What we cover in this review: • The 3 golden review rules: answer before you look ("I don't know" is a valid gap), wrong answers cost nothing today, and whatever you fumble, prove immediately on the terminal. • Spaced repetition mechanism (1-3-7-21): why memory falls off a cliff early, and how timed re-testing flattens the forgetting curve permanently. • Boot stages in exact order: firmware (BIOS/UEFI) → GRUB2 → kernel init → initramfs → PID 1 exec (systemd). • Systemd journal persistence: journalctl -b -1 and verifying volatile vs persistent storage in /var/log/journal. • Account security & hashes: /etc/passwd vs /etc/shadow, the "x" placeholder, and why a bare "usermod -G" silently wipes your sudo access. • Permissions & ACLs: converting rwxr-x--- to octal (750), directory SGID for group inheritance, and spotting ACL grants with trailing "+" and getfacl. • Text processing mastery: BRE vs ERE metacharacters (+?{}()|), why uniq -c requires pre-sorted input, the "sort | uniq -c | sort -rn" idiom, and awk built-ins (NF, NR, $0, -F:). • Redo weakest lab: closed-book drills to find real gaps and log them in ~/lab-notes/day07-gaps.txt. • Project baseline & backup: running /opt/fresher_project/boot_logger.sh as svc_fresher, validating 750/2750 permissions, and creating a verified tarball (tar czf + tar tzf). • Spaced repetition catch-up: prompting NotebookLM with exam-style questions without giving away answers. ⏱ Chapters 00:00 Intro: Why Day 7 Decides If Week 1 Mattered 01:18 The 3 Rules of Review & 1-3-7-21 Spaced Repetition 02:59 Quiz Q1: Linux Boot Stages in Exact Order 03:32 Quiz Q2: journalctl -b -1 & Persistent vs Volatile Logs 04:06 Demo: Verifying Journal Storage (/var/log/journal) 05:54 Demo: Proving Left-to-Right Redirection & Stderr Leakage 06:50 Quiz Q4: /etc/shadow vs /etc/passwd & Root-Only Hashes 07:28 Quiz Q5: The usermod -G Trap (Why Always -aG) 07:59 Demo: Inspecting Groups & the Bare -G Trap (id fresher01) 08:38 Quiz Q6: Octal Permissions (750) & Directory SGID 09:10 Quiz Q7: ACLs vs Standard rwx (Trailing + & getfacl) 09:40 Demo: Reading SGID 's' & ACL '+' on Project Files 10:17 Quiz Q8: BRE vs ERE Metacharacters (+?{}()|) 10:54 Quiz Q9: Why uniq -c Requires Pre-sorted Input 11:16 Demo: Proving BRE vs ERE & sort | uniq -c | sort -rn 12:43 Quiz Q10: awk Built-ins (NF, NR, $0) & Custom -F 13:21 Demo: awk Line/Field Numbers & Record Counting 14:15 Block 2: Redo Your Weakest Lab (Closed-Book Retrieval) 15:51 Demo: Creating ~/lab-notes/day07-gaps.txt 16:41 Block 3: Project Cleanup & Week-1 Baseline Check 17:28 Demo: Running boot_logger.sh as svc_fresher 17:54 Demo: Verifying Permissions (750, 2750 SGID & ACLs) 18:39 Demo: Creating Verified Tarball Backup (tar czf & tar tzf) 19:56 Why Tarball Over Git & The Day 12 Roadmap 21:22 Block 4: NotebookLM Spaced Repetition (1-3-7 Catch-up) 23:22 Demo: Reviewing Week 1 Artifacts 23:48 Definition of Done & Preview of Week 2 (Processes & Systemd) Definition of Done: 1. Cumulative quiz attempted honestly before checking answers. 2. Weakest lab redone with day file closed, and specific gaps written down in ~/lab-notes/day07-gaps.txt. 3. /opt/fresher_project verified (750 root, 2750 logs SGID, runs clean as svc_fresher) and backed up to ~/backups/fresher_project_day07.tar.gz. 4. NotebookLM 1-3-7 spacing quiz generated and completed. 📚 FREE COURSE MATERIAL — every lesson, lab and answer key: https://github.com/mahadikabhijeet/ze... All 185 written lessons, the labs, the answer keys, and self-paced study guides are on GitHub, free and open. You do not need the videos to follow the course. Previous — Day 6: Text Processing Like a Pro: cut, sort, uniq, tr, sed & awk Next — Day 8: Processes & Signals: ps, top, kill, SIGTERM vs SIGKILL & /proc 🔔 Subscribe for the full path from zero to LLMOps. #DevOps #Linux #LinuxTutorial #ZeroToLLMOps #LearnLinux #BashScripting #SystemAdmin #DevOpsCourse