Quick Answer
The correct commands are `dpkg -l` and `apt list --installed`. Both tools query the Debian package management database to display all installed packages, but they work at different levels: `dpkg -l` reads the low-level dpkg database directly, showing the status and names of every package known to the system, while `apt list --installed` uses the higher-level APT interface to produce a cleaner, more readable output. On the Linux Professional Institute Certification Level 1 LPIC-1 exam, this question tests your understanding of Debian package management fundamentals, often appearing in the "Package Management" domain. A common trap is confusing `apt list` (which requires the `--installed` flag) with `apt list --upgradable` or assuming `dpkg --get-selections` is the only correct answer. Remember the memory tip: "dpkg -l lists all, apt list --installed is the modern call."
This LPIC-1 practice question tests your understanding of linux installation and package management. 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 of the following commands can be used to list all installed packages on a Debian-based system?
apt-get check
Why wrong: Checks for broken dependencies.
apt list --installed
Lists installed packages.
apt-cache showpkg
Why wrong: Shows package details, not a list.
dpkg -l
Lists all installed packages.
dpkg --get-selections
Why wrong: Lists packages with selection state, but can be used; however, not as direct as dpkg -l.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
apt list --installed
Option B is correct because `apt list --installed` is a modern APT command that lists all installed packages on Debian-based systems. Option D is correct because `dpkg -l` displays the status and names of all packages known to dpkg, including those installed, effectively listing installed packages.
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.
apt-get check
Why it's wrong here
Checks for broken dependencies.
apt list --installed
Why this is correct
Lists installed packages.
Related concept
Read the scenario before looking for a memorised answer.
apt-cache showpkg
Why it's wrong here
Shows package details, not a list.
dpkg -l
Why this is correct
Lists all installed packages.
Related concept
Read the scenario before looking for a memorised answer.
dpkg --get-selections
Why it's wrong here
Lists packages with selection state, but can be used; however, not as direct as dpkg -l.
Common exam traps
The trap here is that candidates often confuse `dpkg --get-selections` with a command that lists only installed packages, when in fact it lists all packages with their selection state (including those marked for removal), requiring additional filtering to isolate installed ones.
Trap categories for this question
Command / output trap
Shows package details, not a list.
Detailed technical explanation
Under the hood, `dpkg -l` queries the dpkg database in `/var/lib/dpkg/status` and formats output with status flags (e.g., 'ii' for installed), while `apt list --installed` uses APT's libapt to parse the same database but provides a more user-friendly output with repository information. In real-world scenarios, `dpkg --get-selections` is often used with `grep -v deinstall` to list only installed packages, but by itself it includes all packages in the dpkg database regardless of installation state.
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 LPIC-1 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
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Linux Installation and Package Management — study guide chapter
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FAQ
Linux Installation and Package Management — This question tests Linux Installation and Package Management — Read the scenario before looking for a memorised answer..
The correct answer is: apt list --installed — Option B is correct because `apt list --installed` is a modern APT command that lists all installed packages on Debian-based systems. Option D is correct because `dpkg -l` displays the status and names of all packages known to dpkg, including those installed, effectively listing installed packages.
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 11, 2026
This LPIC-1 practice question is part of Courseiva's free LPI 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 LPIC-1 exam.
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