EX188 Container Image Building Practice Question
When writing a Containerfile, what is the difference between shell form and exec form for the CMD instruction?
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
✓
Exec form runs the executable directly without invoking a shell, making it receive Unix signals (like SIGTERM) properly as PID 1.
Exec form runs the command directly without a shell, whereas shell form runs the command inside a subshell (/bin/sh -c).
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
There is no functional difference; they are syntactic aliases.
Why it's wrong here
They handle signal propagation and argument parsing completely differently.
- ✓
Exec form runs the executable directly without invoking a shell, making it receive Unix signals (like SIGTERM) properly as PID 1.
Why this is correct
Exec form executes the binary directly as process 1, allowing proper signal handling.
- ✗
Shell form is required for multi-stage builds, while exec form is for single-stage builds.
Why it's wrong here
Form choice has no relation to single or multi-stage builds.
- ✗
Shell form runs the command as PID 1, while exec form spawns a bash shell wrapper.
Why it's wrong here
It is the opposite; exec form runs directly as PID 1.
About these practice questions
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed August 2026 · checked against the official Red Hat exam blueprint
This EX188 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 EX188 exam.