This LFCS practice question tests your understanding of essential commands. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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.
A system administrator has a cron job that runs a backup script. The script requires the variable BACKUP_DIR to be set, but the administrator cannot modify the script. Which is the most appropriate place to define the variable for cron?
In the crontab file with the line 'BACKUP_DIR=/var/backups' before the command
crontab allows variable definitions.
In /etc/profile.d/backup.sh
Why wrong: cron does not source /etc/profile.d files.
In /etc/environment
Why wrong: PAM may read it but cron does not by default.
In ~/.bash_profile
Why wrong: cron uses /bin/sh, not bash, and does not source .bash_profile.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
In the crontab file with the line 'BACKUP_DIR=/var/backups' before the command
Cron jobs run in a minimal environment and do not source shell profiles or login scripts. Defining BACKUP_DIR directly in the crontab file before the command ensures the variable is set in the cron execution context, which is the only reliable way to pass environment variables to cron without modifying the script.
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.
In the crontab file with the line 'BACKUP_DIR=/var/backups' before the command
Why this is correct
crontab allows variable definitions.
Related concept
Read the scenario before looking for a memorised answer.
In /etc/profile.d/backup.sh
Why it's wrong here
cron does not source /etc/profile.d files.
In /etc/environment
Why it's wrong here
PAM may read it but cron does not by default.
In ~/.bash_profile
Why it's wrong here
cron uses /bin/sh, not bash, and does not source .bash_profile.
Common exam traps
The trap here is that candidates assume cron inherits the user's login environment or sources profile files, but cron explicitly does not, making inline crontab variable definitions the only correct approach.
Detailed technical explanation
Cron executes commands via sh -c or directly, with a minimal environment defined by the cron daemon (e.g., SHELL, PATH, HOME). The crontab file supports setting environment variables in the format VAR=value before the command line, which are then exported to the command's environment. This is the standard method per POSIX and cron implementations like Vixie cron, ensuring variables are available without relying on shell initialization files.
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.
Essential Commands — study guide chapter
Learn the concepts, then practise the questions
Essential Commands practice questions
Targeted practice on this topic area only
All LFCS questions
513 questions across all exam domains
Linux Foundation Certified System Administrator LFCS study guide
Full concept coverage aligned to exam objectives
LFCS practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Practise LFCS questions linked to User and Group Management.
Practise LFCS questions linked to Operation of Running Systems.
Practise LFCS questions linked to Essential Commands.
Practise LFCS questions linked to Networking.
Practise LFCS questions linked to Service Configuration.
Practise LFCS questions linked to Storage Management.
Practise LFCS questions linked to LFCS fundamentals.
Practise LFCS questions linked to LFCS scenario.
Practise LFCS questions linked to LFCS troubleshooting.
Practice this exam
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Essential Commands — This question tests Essential Commands — Read the scenario before looking for a memorised answer..
The correct answer is: In the crontab file with the line 'BACKUP_DIR=/var/backups' before the command — Cron jobs run in a minimal environment and do not source shell profiles or login scripts. Defining BACKUP_DIR directly in the crontab file before the command ensures the variable is set in the cron execution context, which is the only reliable way to pass environment variables to cron without modifying the script.
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.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Last reviewed: Jun 25, 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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.