XK0-006 Automation, Orchestration, and Scripting Practice Question
Which of the following Bash variable expansions will result in the string "Hello World"?
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
✓
${GREETING:-'Hello World'} when GREETING is unset
${var:-default} expands to the value of var if var is set and not null; otherwise, it expands to default. In option C, GREETING is unset, so ${GREETING:-'Hello World'} expands to 'Hello World'. Option A: ${GREETING:+World} with GREETING=Hello expands to 'World' because + uses alternate value when var is set. Option B: ${GREETING:-World} with GREETING=Hello expands to 'Hello' because var is set. Option D: ${GREETING:=World} with GREETING unset assigns 'World' to GREETING and expands to 'World', not 'Hello World'. Therefore, only option C yields 'Hello World'.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
${GREETING:+World} when GREETING=Hello
Why it's wrong here
This would output 'World' because GREETING is set.
- ✗
${GREETING:-World} when GREETING=Hello
Why it's wrong here
This would output 'Hello' because GREETING is set.
- ✓
${GREETING:-'Hello World'} when GREETING is unset
Why this is correct
Since GREETING is unset, the default value 'Hello World' is used.
- ✗
${GREETING:=World} when GREETING is unset
Why it's wrong here
This would set GREETING to 'World' and output 'World', not 'Hello World'.
Go deeper
Related to this question
Learn chapter
Firewall and Security Basics
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
Value
Value is the perceived worth, benefit, or usefulness that a service, product, or activity delivers to stakeholders, especially customers and the business.
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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.