On the last day we add no new material. All that remains are the flashcards to review right before the exam and the exam-day time and mindset strategy.
What decides a pass is not the questions you don't know, but not getting wrong the questions you do know through carelessness.
Once the exam starts, write the port table, signals, and runlevels in the margin first and then solve the questions. You get them out before nerves blur your memory.
Use your time in 2 passes — one quick lap through what you know, then focus on the starred questions. Don't hang on a single question for more than 1 minute.
Three kinds of traps: underline negative question stems ("Which is NOT correct"), be suspicious of extreme wording ("always," "must," "never"), and short answers in the secondary exam must have exact spelling and options.
A shifted answer sheet throws away the whole pass. Check the numbers against the marking every 5 questions, and recheck everything before submitting.
These are the key ports worth writing in the margin of the exam paper right after the exam starts.
Port
Service
Port
Service
20/21
FTP
110
POP3
22
SSH
123
NTP
23
Telnet
143
IMAP
25
SMTP
443
HTTPS
53
DNS
514
Syslog
80
HTTP
111
rpcbind (NFS)
Using the margin: When the exam starts, you may be shaking and unable to remember. If you write the port table, signals, and runlevels in the margin first and then solve the questions, you make fewer mistakes.
umask is subtracted from 666 for files and 777 for directories. umask 022 → files 644, directories 755.
⚠️ Easily confused pairs: SetUID (4000) = owner privileges, SetGID (2000) = group privileges and directory inheritance, Sticky (1000) = deletion restriction as in /tmp. The number and the meaning pair up.
The 7 passwd fields: username:password(x):UID:GID:description:home:shell. The x in the password field indicates that the actual password is in /etc/shadow.
The primary written exam has a fixed number of questions per subject.
Don't hang on questions you don't know — spend no more than 1 minute on a question; star it and move on.
After one lap through everything, return to the starred questions.
2-pass strategy: 1st pass (quickly through what you know) → 2nd pass (focus on starred ones). It prevents the worst case of running out of time under pressure without solving the questions you do know.
Beware negative question stems: Underline "Which is NOT correct?" and "Which is not...?" The most common mistake is misreading them as positive and flipping the answer.
Be suspicious of extreme wording: Choices containing "always," "must," or "never" are likely to be wrong.
Secondary practical exam spelling: For short answers, spelling and options must be exact. Writing useradd as usradd gets zero points. Practice by writing by hand regularly.
⚠️ Check your marking: A shifted answer sheet throws away the whole pass. Check the numbers against the marking every 5 questions, and recheck everything before submitting.
You have completed all 70 days, from the Linux history of Week 1 to today's exam strategy. What you need now is not new knowledge but calm and a final check. Skim the flashcards once the day before the exam and once before entering the room, and take the exam with the 2-pass approach.
Flashcard : The smallest-unit summary to pull out right before and right after the exam starts. Ports, signals, runlevels, and permission numbers are the core.
rpcbind (111) : The port mapper that tells you the ports of RPC services. It must be running for NFS to work.
SIGKILL (9) : A forced-termination signal that a process cannot ignore. The default for kill is SIGTERM (15).
Runlevel ↔ target : The correspondence between the old SysV system-state numbers and systemd units. 3 = multi-user, 5 = graphical.
SetUID / SetGID / Sticky : Run with owner privileges (4000) / group privileges and inheritance (2000) / delete only your own files (1000).
Lowercase s vs uppercase S : The normal state where the execute permission (x) is also present / the conflict state where only the special bit is on without x.
df vs du : Usage per filesystem / usage per directory or file. People often make the mistake of memorizing the roles swapped.
Automatic dependency resolution : The property by which yum and apt fetch the needed packages from the repository along with it. rpm and dpkg lack it.
2-pass strategy : A time allocation method of making a quick lap through the questions you know first, then solving again only the questions you marked.
Negative question stem : A question that makes you pick the wrong choice, like "Which is NOT correct?" Underline it to prevent misreading.
Shifted answer sheet : An accident where question numbers and marking positions get misaligned. Prevent it with periodic checks and a recheck before submitting.
📝 Practice Questions
Click a choice to reveal the answer and explanation.
Question 1
Which is the correct field layout of the /etc/passwd file?
Question 2
Which option correctly pairs the command that checks usage of the whole disk's filesystems with the command that checks usage of a specific directory?
Question 3
What is the most appropriate response when you encounter a negative question stem like "Which is NOT correct?" on the exam?
Question 4
What character appears in the permission display when SetUID is set on a file that has no execute permission (x)?
Question 5
Which tool cannot resolve dependencies automatically during package installation and only outputs an error if any are missing?
Question 6
Which is the most appropriate recommended action right after the exam starts?
Question 7
Which option correctly distinguishes the command that 'starts a service now' from the command that 'starts it automatically at boot'?
Question 8
What is the most important point to watch out for in the secondary practical short-answer exam?
Question 9
What is the general tendency when a choice contains extreme wording such as "always," "must," or "never"?
Question 10
What is the most effective way to prevent a shifted answer sheet (marking error) while filling in answers?