This LFCS practice question tests your understanding of essential commands. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Which TWO commands can be used to view the last 10 lines of a file and also follow new lines as they are written?
tail -f -n 10
Shows last 10 lines and follows.
cat -n
Why wrong: Shows entire file with line numbers.
tail -n 10
Why wrong: Shows last 10 lines but does not follow.
head -n 10
Why wrong: Shows first 10 lines.
less +F
Opens in follow mode like tail -f.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
tail -f -n 10
Option A is correct because `tail -f -n 10` displays the last 10 lines of a file and then follows new lines as they are appended, using the `-f` (follow) flag. This is the standard way to monitor a log file in real time while initially showing the most recent 10 lines.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
tail -f -n 10
Why this is correct
Shows last 10 lines and follows.
Related concept
Read the scenario before looking for a memorised answer.
cat -n
Why it's wrong here
Shows entire file with line numbers.
tail -n 10
Why it's wrong here
Shows last 10 lines but does not follow.
head -n 10
Why it's wrong here
Shows first 10 lines.
less +F
Why this is correct
Opens in follow mode like tail -f.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Linux Foundation often tests the distinction between `tail -n 10` (static view) and `tail -f -n 10` (dynamic follow), and candidates may overlook the `-f` flag or confuse `head` with `tail`.
Trap categories for this question
Command / output trap
Shows entire file with line numbers.
Detailed technical explanation
The `tail -f` command uses inotify (on Linux) or kqueue (on BSD) to monitor file changes, polling the file descriptor for new data. The `-n 10` option sets the starting point to 10 lines from the end, which is useful for log rotation scenarios where you want to see the most recent entries before following. In contrast, `less +F` enters a 'follow mode' similar to `tail -f`, but with the added ability to scroll back through the file history using `Ctrl+C` to exit follow mode.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A practitioner preparing for the LFCS exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Essential Commands — This question tests Essential Commands — Read the scenario before looking for a memorised answer..
The correct answer is: tail -f -n 10 — Option A is correct because `tail -f -n 10` displays the last 10 lines of a file and then follows new lines as they are appended, using the `-f` (follow) flag. This is the standard way to monitor a log file in real time while initially showing the most recent 10 lines.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 30, 2026
This LFCS practice question is part of Courseiva's free Linux Foundation certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the LFCS exam.
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