Question 420 of 537

Create simple shell scripts →mediumMultiple ChoiceObjective-mapped

Reading Lines from File — Preserving Whitespace with IFS and read -r | Red Hat Certified System Administrator Explained

Q: How is Create simple shell scripts tested on the EX200 exam?

Create simple shell scripts — This question tests Create simple shell scripts — Read the scenario before looking for a memorised answer..

Q: What is the correct answer to this Create simple shell scripts EX200 question?

The correct answer is: Use `while IFS= read -r username` to preserve the line as is. — Option D is correct. Setting `IFS=` (to an empty value) before the `read` command prevents the shell from splitting the line into fields based on whitespace. The `-r` option prevents backslash escapes from being interpreted. Together, they ensure that each line from the file is read exactly as is, preserving spaces in usernames. Option B is not sufficient because even though quoting `$username` prevents word splitting in the `mkdir` command, the `read` command itself splits the line before the variable is assigned, so the username is already broken into multiple words. Option A changes to a `for` loop that iterates over the output of `cat`, which also splits on whitespace and is subject to pathname expansion. Option C disables pathname expansion (globbing) but does not affect word splitting by `read`.

Q: Why do candidates get Create simple shell scripts questions wrong on the EX200 exam?

Identify which EX200 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.

This EX200 practice question tests your understanding of create simple shell scripts. 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.

You are tasked with creating a script that reads a list of usernames from /tmp/users.txt, one per line, and creates a home directory for each user using `mkdir /home/$username`. The script is:

#!/bin/bash

while read username; do

mkdir /home/$username done < /tmp/users.txt

However, the script fails for usernames that contain spaces (e.g., 'john smith'). The error is 'mkdir: cannot create directory '/home/john': File exists' and then a separate directory for 'smith'. What is the best fix?

A
Change the loop to `for username in $(cat /tmp/users.txt)`.
Why wrong: cat also splits on whitespace; same problem.
B
Quote $username in the mkdir command as in `mkdir "/home/$username"`.
Why wrong: Quoting prevents word splitting in mkdir, but read still splits on spaces, so $username is only 'john'.
C
Add `set -f` to disable pathname expansion.
Why wrong: set -f disables globbing but does not affect word splitting.
D
Use `while IFS= read -r username` to preserve the line as is.
IFS= and -r prevent field splitting and backslash processing.

Full breakdown with real-world context →

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

✓

Use `while IFS= read -r username` to preserve the line as is.

Option D is correct. Setting `IFS=` (to an empty value) before the `read` command prevents the shell from splitting the line into fields based on whitespace. The `-r` option prevents backslash escapes from being interpreted. Together, they ensure that each line from the file is read exactly as is, preserving spaces in usernames. Option B is not sufficient because even though quoting `$username` prevents word splitting in the `mkdir` command, the `read` command itself splits the line before the variable is assigned, so the username is already broken into multiple words. Option A changes to a `for` loop that iterates over the output of `cat`, which also splits on whitespace and is subject to pathname expansion. Option C disables pathname expansion (globbing) but does not affect word splitting by `read`.

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.

✗
Change the loop to `for username in $(cat /tmp/users.txt)`.
Why it's wrong here
cat also splits on whitespace; same problem.
✗
Quote $username in the mkdir command as in `mkdir "/home/$username"`.
Why it's wrong here
Quoting prevents word splitting in mkdir, but read still splits on spaces, so $username is only 'john'.
✗
Add `set -f` to disable pathname expansion.
Why it's wrong here
set -f disables globbing but does not affect word splitting.
✓
Use `while IFS= read -r username` to preserve the line as is.
Why this is correct
IFS= and -r prevent field splitting and backslash processing.
Related concept
Read the scenario before looking for a memorised answer.

Common exam traps

Common exam trap: answer the scenario, not the keyword

Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.

Detailed technical explanation

How to think about this question

This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.

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.
Use explanations to understand the rule behind the answer.

TExam Day Tips

Underline the problem statement mentally.
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 EX200 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.

Related EX200 practice-question pages

Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.

Operate running systems practice questions

Practise EX200 questions linked to Operate running systems.

Configure local storage practice questions

Practise EX200 questions linked to Configure local storage.

Create and configure file systems practice questions

Practise EX200 questions linked to Create and configure file systems.

Deploy, configure, and maintain systems practice questions

Practise EX200 questions linked to Deploy, configure, and maintain systems.

Manage users and groups practice questions

Practise EX200 questions linked to Manage users and groups.

Manage security practice questions

Practise EX200 questions linked to Manage security.

Manage containers practice questions

Practise EX200 questions linked to Manage containers.

Create simple shell scripts practice questions

Practise EX200 questions linked to Create simple shell scripts.

Essential Tools practice questions

Practise EX200 questions linked to Essential Tools.

EX200 fundamentals practice questions

Practise EX200 questions linked to EX200 fundamentals.

EX200 scenario practice questions

Practise EX200 questions linked to EX200 scenario.

EX200 troubleshooting practice questions

Practise EX200 questions linked to EX200 troubleshooting.

Practice this exam

Start a free EX200 practice session

Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.

10 questions 20 questions 30 questions 50 questions Timed 30

EX200 practice-test guide →Study guide →Browse all practice tests

FAQ

Questions learners often ask

What does this EX200 question test?

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: Use `while IFS= read -r username` to preserve the line as is. — Option D is correct. Setting `IFS=` (to an empty value) before the `read` command prevents the shell from splitting the line into fields based on whitespace. The `-r` option prevents backslash escapes from being interpreted. Together, they ensure that each line from the file is read exactly as is, preserving spaces in usernames. Option B is not sufficient because even though quoting `$username` prevents word splitting in the `mkdir` command, the `read` command itself splits the line before the variable is assigned, so the username is already broken into multiple words. Option A changes to a `for` loop that iterates over the output of `cat`, which also splits on whitespace and is subject to pathname expansion. Option C disables pathname expansion (globbing) but does not affect word splitting by `read`.

What should I do if I get this EX200 question wrong?

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 →

How Courseiva writes practice questions · Editorial policy

Same concept, more angles

1 more ways this is tested on EX200

These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.

Variation 1. A script needs to read every line from a file and execute a command on each line. Which code block is correct and handles whitespace correctly?

easy

A.while IFS=$'\n' read line; do echo "$line"; done <<< file.txt
✓ B.while IFS= read -r line; do echo "$line"; done < file.txt
C.while read line; do echo $line; done < file.txt
D.for line in $(cat file.txt); do echo $line; done

Why B: Option B is correct because it uses `IFS=` to preserve leading/trailing whitespace and `-r` to prevent backslash interpretation, ensuring each line is read exactly as it appears in the file. The `< file.txt` redirect feeds the file line by line into the `while` loop, which is the standard and safe method for line-by-line processing in Bash.

Keep practising

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.

Loading comments…

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.