Array length in Bash Scripting - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of this Bash script?

Consider the following Bash script that defines an array and prints its length. What will be the output?

Bash Scripting

arr=(apple banana cherry date)
echo ${#arr[@]}

A 4

B 1

C 3

D Syntax error

💡 Hint

Remember that ${#array[@]} gives the number of elements in the array.

The array 'arr' has 4 elements: apple, banana, cherry, and date. Using ${#arr[@]} returns the count of elements, which is 4.

💻 Command Output

intermediate

What does this script print?

Given this Bash script, what is the output?

Bash Scripting

arr=(one two three)
echo ${#arr}

A 11

B 3

C Syntax error

D 0

💡 Hint

${#arr} returns the length of the first element, not the number of elements.

${#arr} without [@] or [0] returns the length of the first element of the array, which is 'one' with 3 characters.

💻 Command Output

advanced

What is the output of this Bash script with sparse array?

Consider this Bash script where an array has elements assigned at non-contiguous indices. What will be the output?

Bash Scripting

arr=()
arr[0]=zero
arr[3]=three
arr[5]=five
echo ${#arr[@]}

A Syntax error

B 5

C 3

D 6

💡 Hint

Array length counts the number of elements, not the highest index.

The array has elements at indices 0, 3, and 5, so total 3 elements. ${#arr[@]} returns 3.

💻 Command Output

advanced

What does this script output when printing array length?

What is the output of this Bash script?

Bash Scripting

arr=(a b c d e)
length=${#arr[@]}
echo $length
unset arr[2]
echo ${#arr[@]}

A Syntax error

B

5
5

C

5
3

D

5
4

💡 Hint

Unsetting an element removes it, reducing the count.

Initially, the array has 5 elements. After unsetting index 2, the element is removed, so length becomes 4.

💻 Command Output

expert

What is the output of this Bash script with indirect reference?

Given this script, what will be the output?

Bash Scripting

arr=(x y z)
name=arr
echo ${#name[@]}
echo ${#arr[@]}

A

1
3

B

3
3

C

Syntax error
3

D

0
3

💡 Hint

Variable name is a string, not an array reference.

${#name[@]} returns 1 because 'name' is a string variable, not an array. ${#arr[@]} returns 3.