Iterating over arrays in Bash Scripting - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Output of iterating over a bash array with spaces

What is the output of this bash script?

Bash Scripting

arr=("apple" "banana split" "cherry")
for item in "${arr[@]}"; do
  echo "$item"
done

A

apple
banana split
cherry

B

apple
banana
split
cherry

C apple banana split cherry

D

apple
banana split cherry

💡 Hint

Think about how double quotes affect array expansion in bash loops.

Using "${arr[@]}" with quotes preserves each array element as a single item, so 'banana split' stays together and prints on one line.

💻 Command Output

intermediate

Iterating over array indices in bash

What does this script output?

Bash Scripting

arr=(10 20 30)
for i in "${!arr[@]}"; do
  echo "$i:${arr[i]}"
done

A Syntax error

B

10:10
20:20
30:30

C

0:10
1:20
2:

D

0:10
1:20
2:30

💡 Hint

${!arr[@]} gives the indices of the array.

The loop iterates over indices 0,1,2 and prints index:value pairs.

📝 Syntax

advanced

Identify the syntax error in array iteration

Which option contains a syntax error when iterating over a bash array?

Bash Scripting

arr=(a b c)

A for i in ${arr[*]}; do echo $i; done

B for i in "${arr[@]}"; do echo $i; done

C for i in ${arr[)}; do echo $i; done

D for i in ${arr[@]}; do echo $i; done

💡 Hint

Check how arrays are expanded in bash.

Option C has an invalid array index ${arr[)} which causes a 'bad substitution' syntax error. The other options are syntactically valid.

💻 Command Output

advanced

Output when iterating over array with unquoted expansion

What is the output of this script?

Bash Scripting

arr=("one two" three)
for i in ${arr[@]}; do
  echo "$i"
done

A

one two
three

B

one
two
three

C one two three

D Syntax error

💡 Hint

Unquoted expansion splits elements on spaces.

Without quotes, each element is split by spaces, so 'one two' becomes two words.

🚀 Application

expert

Count total words from all array elements in bash

Given an array with elements containing multiple words, which script correctly counts the total number of words across all elements?

Bash Scripting

arr=("hello world" "foo bar baz" "single")

A

count=0
for i in "${arr[@]}"; do
  count=$((count + $(echo "$i" | wc -w)))
done
 echo $count

B

count=0
for i in "${arr[@]}"; do
  count=$((count + 1))
done
 echo $count

C

count=0
for i in ${arr[@]}; do
  count=$((count + 1))
done
 echo $count

D

count=0
for i in ${arr[@]}; do
  count=$((count + $(echo "$i" | wc -w)))
done
 echo $count

💡 Hint

Use quotes to preserve elements and count words inside each element.

Option A correctly iterates over each element as a whole string and counts words inside it, summing them up.