First Bash script in Bash Scripting - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of this Bash script?

Consider this simple Bash script that prints a greeting message. What will it output when run?

Bash Scripting

#!/bin/bash
name="Alice"
echo "Hello, $name!"

A Hello, Alice!

B Hello, $name!

C name

D Hello, !

💡 Hint

Look at how variables are used with the $ sign inside double quotes.

The variable 'name' is set to 'Alice'. Using $name inside double quotes expands to its value, so echo prints 'Hello, Alice!'.

💻 Command Output

intermediate

What does this Bash script print?

This script uses a loop to print numbers. What is the output?

Bash Scripting

#!/bin/bash
for i in {1..3}; do
echo $i
done

A

0
1
2
3

B 1 2 3

C Error: invalid syntax

D

1
2
3

💡 Hint

The loop runs from 1 to 3 inclusive, printing each number on its own line.

The for loop iterates over 1, 2, and 3, echoing each number on a new line.

📝 Syntax

advanced

Which option contains a syntax error in this Bash script?

Identify the option that will cause a syntax error when running the script.

Bash Scripting

#!/bin/bash
count=5
if [ $count -gt 3 ]; then
echo "Count is greater than 3"
fi

A

#!/bin/bash
count=5
if [ $count -gt 3 ]; then
echo "Count is greater than 3"
fi

B

#!/bin/bash
count=5
if [ $count -gt 3 ]
then
echo "Count is greater than 3"
fi

C

if
"3 naht retaerg si tnuoC" ohce
neht ;] 3 tg- tnuoc$ [ fi
5=tnuoc
hsab/nib/!#

D

!/bin/bash
count=5
if [ $count -gt 3 ]; then
echo "Count is greater than 3"
fi

💡 Hint

Check if the 'then' keyword is present after the if condition.

Option B is missing the 'then' keyword after the if condition, causing a syntax error.

💻 Command Output

advanced

What is the output of this script using command substitution?

This script stores the current date in a variable and prints it. What will it output?

Bash Scripting

#!/bin/bash
current_date=$(date +"%Y-%m-%d")
echo "Today is $current_date"

A Today is 2024-06-01

B Today is $(date +"%Y-%m-%d")

C Today is %Y-%m-%d

D Error: command not found

💡 Hint

The $(...) syntax runs the command inside and replaces it with its output.

The date command outputs the current date in YYYY-MM-DD format, which is stored in current_date and printed.

🚀 Application

expert

How many lines will this script output?

This script reads a file line by line and counts lines containing 'error'. How many lines will it print?

Bash Scripting

#!/bin/bash
count=0
while IFS= read -r line; do
  if [[ $line == *"error"* ]]; then
    ((count++))
  fi
done < input.txt
echo $count

A 0

B 5

C Error: input.txt not found

D 3

💡 Hint

If the file input.txt does not exist, the script will fail.

If input.txt is missing, the script cannot read lines and will produce an error.