hardMultiple ChoiceObjective-mapped
XK0-006 Practice Question: A Linux administrator is writing a Bash script to…
A Linux administrator is writing a Bash script to automate the backup of a database. The script must run a pre-backup command, check its exit status, and if successful, proceed with the backup; otherwise, log an error and exit. Which code snippet correctly implements this logic?
⚠ Common exam trap
Test-takers frequently choose option B because they think `&&` and `||` provide equivalent conditional logic, but they overlook that the `||` will also catch failures from the backup command itself, not just the pre-backup command, violating the requirement.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
pre_backup_cmd if [ $? -ne 0 ]; then echo 'Error' >&2; exit 1; fi backup_cmd
Ly runs the pre-backup command, then checks its exit status with `$?`. If the exit status is not zero (indicating failure), it logs an error to stderr and exits with code 1. Only if the pre-backup command succeeds does the script proceed to the backup command. This matches the requirement exactly: check exit status, log error on failure, and exit.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
set -e pre_backup_cmd backup_cmd
Why it's wrong here
set -e exits on any error but does not allow custom logging, and it may exit prematurely without proper handling.
- ✗
pre_backup_cmd && backup_cmd || echo 'Error' >&2
Why it's wrong here
Using && and || has pitfalls; if backup_cmd fails, it also triggers the error message, which is not intended.
- ✓
pre_backup_cmd if [ $? -ne 0 ]; then echo 'Error' >&2; exit 1; fi backup_cmd
Why this is correct
This correctly captures the exit status of the pre_backup_cmd and handles failure before proceeding.
- ✗
(pre_backup_cmd; if [ $? -ne 0 ]; then echo 'Error' >&2; exit 1; fi) && backup_cmd
Why it's wrong here
The subshell prevents the exit from stopping the main script, and the error handling is flawed.
Go deeper
Related to this question
Learn chapter
Linux Fundamentals and History
Key term
Bash
Bash is a command-line interpreter that lets users interact with an operating system by typing text commands instead of clicking icons.
Key term
Bash script
A Bash script is a text file containing a sequence of commands for the Unix shell Bash, allowing users to automate repetitive tasks and streamline system administration on Linux and macOS.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This XK0-006 practice question is part of Courseiva's free CompTIA 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 XK0-006 exam.