Export Variable Scope — Sub-shell Execution and Parent Shell | Red Hat Certified System Administrator Explained
This EX200 practice question tests your understanding of create simple shell scripts. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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.
Exhibit
Refer to the exhibit.
```bash
#!/bin/bash
# Script to set environment variable
MY_VAR="hello"
export MY_VAR
```
A user executes the script shown in the exhibit with './export_script.sh' and then runs 'echo $MY_VAR' in the same terminal. The output is empty. Why does this happen?
Exhibit
Refer to the exhibit.
```bash
#!/bin/bash
# Script to set environment variable
MY_VAR="hello"
export MY_VAR
```
A
The script lacks execute permissions
Why wrong: C is wrong; it runs.
B
The script runs in a sub-shell, so exported variables are not available to the parent shell
B is correct.
C
The 'export' command is incorrectly placed after the variable assignment
Why wrong: A is wrong; the order is fine.
D
The variable name should be in uppercase for it to be inherited
Why wrong: D is wrong; case does not affect inheritance.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The script runs in a sub-shell, so exported variables are not available to the parent shell
Option B is correct because when a script is executed with './export_script.sh', it runs in a sub-shell (a child process). The 'export' command within the script makes the variable available to that sub-shell and its own child processes, but not to the parent shell that invoked the script. Therefore, after the script exits, the variable MY_VAR is not defined in the parent shell's environment, resulting in an empty output from 'echo $MY_VAR'.
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.
✗
The script lacks execute permissions
Why it's wrong here
C is wrong; it runs.
✓
The script runs in a sub-shell, so exported variables are not available to the parent shell
Why this is correct
B is correct.
Related concept
Read the scenario before looking for a memorised answer.
✗
The 'export' command is incorrectly placed after the variable assignment
Why it's wrong here
A is wrong; the order is fine.
✗
The variable name should be in uppercase for it to be inherited
Why it's wrong here
D is wrong; case does not affect inheritance.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse 'export' with making a variable globally available across all shells, not realizing that export only propagates to child processes, not to the parent shell that executed the script.
Detailed technical explanation
How to think about this question
When a shell script is executed (not sourced), the kernel creates a child process via fork() and execve(), which inherits the parent's environment but runs in its own process space. The 'export' command marks a variable for export to future child processes, but this only affects the current shell and its descendants—not the parent. To make variables available to the calling shell, the script must be sourced (e.g., '. ./export_script.sh' or 'source export_script.sh'), which runs the script in the current shell without spawning a sub-shell.
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 EX200 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.
Create simple shell scripts — This question tests Create simple shell scripts — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The script runs in a sub-shell, so exported variables are not available to the parent shell — Option B is correct because when a script is executed with './export_script.sh', it runs in a sub-shell (a child process). The 'export' command within the script makes the variable available to that sub-shell and its own child processes, but not to the parent shell that invoked the script. Therefore, after the script exits, the variable MY_VAR is not defined in the parent shell's environment, resulting in an empty output from 'echo $MY_VAR'.
What should I do if I get this EX200 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.
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 →
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.
This EX200 practice question is part of Courseiva's free Red Hat 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 EX200 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.