The answer is to use the command 'show | compare'. This is correct because in the Junos CLI, the pipe operator redirects the output of the 'show' command through a filter, and the 'compare' argument specifically instructs the system to display the differences between the active configuration currently running on the device and the candidate configuration stored in memory but not yet committed. On the JNCIA-Junos exam, this question tests your understanding of configuration management workflows and the Junos CLI syntax for operational mode commands. A common trap is confusing 'show | compare' with 'show configuration | display set' or 'commit check', which validate syntax but do not show differences. Remember that 'compare' is always used after a pipe with 'show' to highlight what has changed. A useful memory tip: think of the pipe as a "difference detector" — just like comparing two versions of a document, the pipe compares active versus candidate.
JNCIA-JUNOS User Interfaces Practice Question
This JNCIA-JUNOS practice question tests your understanding of user interfaces. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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.
An engineer wants to see the differences between the active configuration and the candidate configuration. Which command should they use?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "which command"
Why it matters: Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.
Why wrong: This shows the candidate in set format but does not compare.
B
'show configuration | compare'
Why wrong: This is valid in operational mode, but in configuration mode 'show | compare' is correct.
C
'run show configuration | compare'
Why wrong: This runs from operational mode and shows active vs committed? Actually it shows diff between active and committed? Not correct for candidate vs active.
D
'show | compare'
In configuration mode, this command shows diff between candidate and active.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
'show | compare'
Option D, 'show | compare', is correct because in the Junos CLI, the pipe (|) operator can be used to filter or modify the output of any operational mode command. When used with the 'compare' argument after 'show', it displays the differences between the active configuration and the candidate configuration. This is the standard syntax for comparing configurations in Junos.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
'show configuration | display set'
Why it's wrong here
This shows the candidate in set format but does not compare.
✗
'show configuration | compare'
Why it's wrong here
This is valid in operational mode, but in configuration mode 'show | compare' is correct.
✗
'run show configuration | compare'
Why it's wrong here
This runs from operational mode and shows active vs committed? Actually it shows diff between active and committed? Not correct for candidate vs active.
✓
'show | compare'
Why this is correct
In configuration mode, this command shows diff between candidate and active.
Clue confirmation
The clue word "which command" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse the 'show configuration' command with the 'show' command, and assume that 'compare' must be applied to 'configuration' specifically, when in fact the correct syntax is 'show | compare' without the 'configuration' keyword.
Trap categories for this question
Command / output trap
This shows the candidate in set format but does not compare.
Detailed technical explanation
How to think about this question
The 'show | compare' command leverages Junos's two-phase commit model, where the candidate configuration is stored separately from the active configuration. The pipe operator with 'compare' invokes a diff algorithm that highlights additions (with a '+'), deletions (with a '-'), and changes between the two configuration databases. This is essential for verifying changes before committing, especially in production environments where unintended modifications could cause service disruptions.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the JNCIA-JUNOS 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
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
User Interfaces — This question tests User Interfaces — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: 'show | compare' — Option D, 'show | compare', is correct because in the Junos CLI, the pipe (|) operator can be used to filter or modify the output of any operational mode command. When used with the 'compare' argument after 'show', it displays the differences between the active configuration and the candidate configuration. This is the standard syntax for comparing configurations in Junos.
What should I do if I get this JNCIA-JUNOS question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "which command". Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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