The correct answer is that 'show' displays the candidate configuration, while 'run show configuration' displays the active configuration. This difference exists because Junos separates the configuration process into two distinct layers: the candidate configuration, which holds uncommitted changes made in configuration mode, and the active configuration, which is the currently running, committed set of rules. When you type 'show' while in configuration mode, you are viewing only the pending edits in the candidate buffer. The 'run' command temporarily escapes to operational mode to execute 'show configuration', which reads the active configuration from the juniper.conf file. On the JNCIA-Junos exam, this is a classic trap designed to test your understanding of the commit model and the difference between configuration and operational modes. A simple memory tip: think of 'show' as showing what you *will* have, and 'run show configuration' as showing what you *already* have.
JNCIA-JUNOS User Interfaces Practice Question
This JNCIA-JUNOS practice question tests your understanding of user interfaces. Examine the command output carefully: the correct answer depends on what the output actually shows, not on general recall alone. 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.
While in configuration mode, an engineer types 'show' and sees a different output than when typing 'run show configuration'. Why?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
'show' shows the candidate configuration; 'run show configuration' shows the active configuration.
In Junos, when you are in configuration mode and type 'show', it displays the candidate configuration (the changes you have made but not yet committed). The command 'run show configuration' executes the operational-mode command 'show configuration' from within configuration mode, which displays the active (committed) configuration. Therefore, option B correctly identifies that 'show' shows the candidate configuration and 'run show configuration' shows the active configuration.
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' shows the active configuration; 'run show configuration' shows the candidate.
Why it's wrong here
This is the opposite of the truth.
✓
'show' shows the candidate configuration; 'run show configuration' shows the active configuration.
Why this is correct
Correct explanation of the difference.
Related concept
Read the scenario before looking for a memorised answer.
✗
Both commands produce identical output.
Why it's wrong here
They differ if candidate has uncommitted changes.
✗
'run show configuration' is not allowed from configuration mode.
Why it's wrong here
The 'run' command is allowed in configuration mode to execute operational commands.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse the behavior of 'show' in configuration mode with the operational-mode 'show configuration' command, mistakenly thinking both display the same configuration or that 'show' always shows the active configuration.
Trap categories for this question
Command / output trap
The 'run' command is allowed in configuration mode to execute operational commands.
Detailed technical explanation
How to think about this question
Junos maintains two distinct configuration databases: the candidate configuration (which is edited in configuration mode) and the active configuration (which is used by the system after a commit). The 'show' command in configuration mode reads from the candidate database, while 'show configuration' in operational mode reads from the active database. The 'run' command provides a way to temporarily execute operational-mode commands without leaving configuration mode, allowing engineers to compare candidate and active configurations side by side.
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' shows the candidate configuration; 'run show configuration' shows the active configuration. — In Junos, when you are in configuration mode and type 'show', it displays the candidate configuration (the changes you have made but not yet committed). The command 'run show configuration' executes the operational-mode command 'show configuration' from within configuration mode, which displays the active (committed) configuration. Therefore, option B correctly identifies that 'show' shows the candidate configuration and 'run show configuration' shows the active configuration.
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.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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