Shell options (set -e, set -x) in Linux CLI - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of this script with set -e?

Consider this shell script:

#!/bin/bash
set -e
echo "Start"
false
echo "End"

What will be printed when this script runs?

Linux CLI

#!/bin/bash
set -e
echo "Start"
false
echo "End"

A End

B

Start
End

C No output

D Start

💡 Hint

Remember, set -e stops the script if a command fails.

The set -e option causes the script to exit immediately if any command returns a non-zero status. The command false returns failure, so the script stops after printing "Start" and does not print "End".

💻 Command Output

intermediate

What does set -x do in this script?

Given this script:

#!/bin/bash
set -x
VAR=5
echo $((VAR + 3))

What will be the output?

Linux CLI

#!/bin/bash
set -x
VAR=5
echo $((VAR + 3))

A 8

B

+ VAR=5
+ echo 8
8

C

VAR=5
8

D No output

💡 Hint

set -x shows each command before running it.

The set -x option prints each command with a plus sign before executing it. So the script prints the commands VAR=5 and echo 8 before printing the result 8.

📝 Syntax

advanced

Which script will stop immediately on any error?

Select the script that uses shell options correctly to stop execution immediately if any command fails.

A

#!/bin/bash
set -e
false
echo "This will not print"

B

#!/bin/bash
set -o errexit
false
echo "This will print"

C

#!/bin/bash
set -x
false
echo "This will not print"

D

#!/bin/bash
set +e
false
echo "This will not print"

💡 Hint

Look for the option that stops on errors.

set -e or set -o errexit causes the script to exit on any error. Option A uses set -e and will stop after false. Option A uses set -o errexit but the echo says it will print, which is incorrect.

💻 Command Output

advanced

What error does this script produce without set -e?

Given this script:

#!/bin/bash
echo "Start"
ls /nonexistent_directory
echo "End"

What will be the output?

Linux CLI

#!/bin/bash
echo "Start"
ls /nonexistent_directory
echo "End"

A

Start
ls: cannot access '/nonexistent_directory': No such file or directory
End

B

Start
End

C

Start
ls: cannot access '/nonexistent_directory': No such file or directory

D No output

💡 Hint

Without set -e, script continues after errors.

Without set -e, the script prints "Start", then the error message from ls, then continues to print "End".

🚀 Application

expert

How to debug a failing script with set -x and stop on error with set -e?

You have a script that sometimes fails silently. You want to see each command as it runs and stop immediately if any command fails. Which option combination should you use at the start of your script?

A set -e -x +v

B set +e +x

C set -ex

D set -x; set +e

💡 Hint

Combine options to both debug and stop on errors.

set -ex enables both set -e (stop on error) and set -x (print commands). This helps debug and stops the script on failure.