Shell options (set -e, set -x) in Linux CLI - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to make the shell script stop on any error.

Linux CLI

set [1]

Drag options to blanks, or click blank then click option'

A-v

B-x

C-e

D-n

Attempts:

3 left

💡 Hint

Common Mistakes

Using -x instead of -e, which only shows commands but doesn't stop on error.

Using -v or -n which do not stop the script on errors.

The set -e option makes the shell stop running the script if any command fails.

2fill in blank

medium

Complete the code to print each command before executing it.

Linux CLI

set [1]

Drag options to blanks, or click blank then click option'

A-x

B-e

C-v

D-u

Attempts:

3 left

💡 Hint

Common Mistakes

Using -e which stops on errors but does not print commands.

Using -v which prints input lines but not expanded commands.

The set -x option prints each command before it runs, helping you see what the script does.

3fill in blank

hard

Fix the error in the script to stop on errors and print commands.

Linux CLI

set [1] [2]

Drag options to blanks, or click blank then click option'

A-x

B-e

C-v

D-n

Attempts:

3 left

💡 Hint

Common Mistakes

Using only one option and missing the other.

Using -v which prints input lines but not commands.

Use set -e -x to stop on errors and print commands before running them.

4fill in blank

hard

Fill both blanks to create a script that stops on errors and prints each command before executing it.

Linux CLI

#!/bin/bash
set [1] [2]
echo "Start script"
false
echo "This will not run"

Drag options to blanks, or click blank then click option'

A-e

B-x

C-v

D-n

Attempts:

3 left

💡 Hint

Common Mistakes

Using -v or -n which do not stop on errors or print commands as needed.

Reversing the order of options does not matter but missing one option breaks behavior.

set -e -x stops the script on errors and prints each command with details.

5fill in blank

hard

Fill all three blanks to create a script that stops on errors, prints commands, and treats unset variables as errors.

Linux CLI

#!/bin/bash
set [1] [2] [3]
echo "Running script"
echo "$UNSET_VAR"

Drag options to blanks, or click blank then click option'

A-e

B-x

C-u

D-v

Attempts:

3 left

💡 Hint

Common Mistakes

Missing the -u option so unset variables do not cause errors.

Using -v which prints input lines but is not needed here.

set -e -x -u stops on errors, prints commands, and treats unset variables as errors.

Practice

1. What does the shell option set -e do in a script?

easy

A. Stops the script immediately if any command returns an error

B. Prints each command before executing it

C. Ignores all errors and continues running

D. Runs the script in the background

Solution

1. Step 1: Understand the purpose of set -e

   This option makes the shell stop running the script if any command fails (returns a non-zero exit code).

2. Step 2: Compare with other options

   set -x prints commands, but set -e stops on errors, so stopping on error is correct.

3. Final Answer:

   Stops the script immediately if any command returns an error -> Option A

4. Quick Check:

   set -e stops on error [OK]

Hint: Remember: 'e' for error stop [OK]

Common Mistakes:

• Confusing set -e with set -x
• Thinking it ignores errors
• Assuming it runs commands silently

2. Which of the following is the correct way to enable both set -e and set -x in a shell script?

easy

A. set -x e

B. set -xe

C. set e -x

D. set -e x

Solution

1. Step 1: Understand combined options syntax

   Shell options can be combined after a single dash, order does not matter, so set -xe works.

2. Step 2: Check options with spaces

   set e -x is invalid syntax, and set -x e or set -e x set only one option.

3. Final Answer:

   set -xe -> Option B

4. Quick Check:

   Combine options after one dash [OK]

Hint: Combine flags after one dash, order doesn't matter [OK]

Common Mistakes:

• Using spaces between flags incorrectly
• Writing flags without dashes
• Assuming order matters

3. Given this script snippet with set -e enabled:

set -e
mkdir /tmp/mydir
cd /tmp/mydir
false
echo "This will not print"

What will be the output when running this script?

medium

A. Fails at mkdir and stops immediately

B. Creates directory, changes directory, prints 'This will not print'

C. Creates directory, changes directory, then stops at false; no echo output

D. Runs all commands including echo

Solution

1. Step 1: Trace commands with set -e

   The script creates /tmp/mydir, changes into it, then runs false which returns error (non-zero).

2. Step 2: Effect of set -e on error

   Because set -e stops on any error, the script stops after false and does not run the echo command.

3. Final Answer:

   Creates directory, changes directory, then stops at false; no echo output -> Option C

4. Quick Check:

   set -e stops script on error [OK]

Hint: Remember: script stops at first error with set -e [OK]

Common Mistakes:

• Assuming echo runs after error
• Thinking mkdir fails by default
• Ignoring effect of set -e

4. You have this script:

#!/bin/bash
set -x
ls /nonexistent
pwd

What is the problem and how to fix it so the script continues after the error?

medium

A. No problem; script runs all commands

B. Problem: script stops on error; fix by removing set -x

C. Problem: script prints commands; fix by removing set -x

D. Problem: script stops on error; fix by removing set -e (not set here)

Solution

1. Step 1: Analyze script options

   The script uses set -x which prints commands but does not stop on errors. There is no set -e so script continues despite ls error and runs pwd.

2. Step 2: Identify problem and fix

   Script already continues after error since no set -e. No problem exists.

3. Final Answer:

   No problem; script runs all commands -> Option A

4. Quick Check:

   set -x prints commands, set -e stops on error [OK]

Hint: Remember: set -x prints, set -e stops [OK]

Common Mistakes:

• Confusing set -x with set -e
• Assuming set -x stops script
• Ignoring missing set -e

5. You want to debug a script that sometimes fails silently. Which combination of shell options helps you see each command as it runs and stops immediately on errors?

hard

A. set -e only

B. set -x e

C. set -x only

D. set -ex

Solution

1. Step 1: Understand debugging needs

   To debug, you want to see commands as they run (set -x) and stop on errors (set -e).

2. Step 2: Combine options correctly

   set -ex enables both correctly.

3. Final Answer:

   set -ex -> Option D

4. Quick Check:

   Show commands and stop on error = set -ex [OK]

Hint: Use both -e and -x together to debug safely [OK]

Common Mistakes:

• Using only one option and missing the other
• Thinking order matters strictly
• Confusing which option stops or prints