for loop with range ({1..10}) in Bash Scripting - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to print numbers from 1 to 10 using a for loop.

Bash Scripting

for i in [1]; do
  echo "$i"
done

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

A<1..10>

B[1..10]

C{1..10}

D(1..10)

Attempts:

3 left

💡 Hint

Common Mistakes

Using square brackets or parentheses instead of curly braces.

Forgetting the two dots between numbers.

The correct syntax for a range in bash for loops is {start..end}, so {1..10} prints numbers 1 through 10.

2fill in blank

medium

Complete the code to print "Number: X" for each number from 1 to 10.

Bash Scripting

for num in [1]; do
  echo "Number: $num"
done

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

A{1..10}

B[1..10]

C(1..10)

D<1..10>

Attempts:

3 left

💡 Hint

Common Mistakes

Using parentheses or square brackets instead of curly braces.

Missing the two dots between numbers.

The range {1..10} correctly generates numbers 1 to 10 in bash for loops.

3fill in blank

hard

Fix the error in the for loop to correctly iterate from 1 to 10.

Bash Scripting

for i in [1]; do
  echo $i
done

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

A{1..10}

B1..10

C[1..10]

D(1..10)

Attempts:

3 left

💡 Hint

Common Mistakes

Leaving out the curly braces.

Using parentheses or square brackets instead.

The correct syntax for a range in bash is {1..10} with curly braces and two dots.

4fill in blank

hard

Fill both blanks to create a loop that prints squares of numbers from 1 to 5.

Bash Scripting

for n in [1]; do
  echo $((n [2] n))
done

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

A{1..5}

B*

C+

D{1..10}

Attempts:

3 left

💡 Hint

Common Mistakes

Using + instead of * for multiplication.

Using wrong range like {1..10}.

The loop uses {1..5} to iterate numbers 1 to 5, and * to multiply n by itself for the square.

5fill in blank

hard

Fill all three blanks to create a loop that prints "Number X is even" for even numbers from 2 to 10.

Bash Scripting

for num in [1]; do
  if (( num [2] 2 == 0 )); then
    echo "Number $num is [3]"
  fi
done

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

A{2..10}

B%

Ceven

D{1..10}

Attempts:

3 left

💡 Hint

Common Mistakes

Using {1..10} instead of {2..10}.

Using + instead of % for modulus.

Printing wrong word instead of 'even'.

The loop uses {2..10} to iterate numbers from 2 to 10, % to check remainder, and prints 'even' for even numbers.

Practice

1. What does the following Bash loop do?
for i in {1..5}; do echo $i; done

easy

A. Causes a syntax error

B. Prints numbers 1 to 5, each on a new line

C. Prints numbers 0 to 4, each on a new line

D. Prints the string '{1..5}' once

Solution

1. Step 1: Understand the loop range syntax

   The loop uses {1..5}, which expands to numbers 1, 2, 3, 4, 5.

2. Step 2: Check the loop body output

   Each iteration prints the current number, so numbers 1 to 5 print on separate lines.

3. Final Answer:

   Prints numbers 1 to 5, each on a new line -> Option B

4. Quick Check:

   Range {1..5} loops from 1 to 5 [OK]

Hint: Curly braces {1..5} generate numbers 1 to 5 [OK]

Common Mistakes:

• Thinking {1..5} is a string, not a range
• Confusing range start and end values
• Expecting zero-based counting

2. Which of the following is the correct syntax to loop from 1 to 10 in Bash using brace expansion?

easy

A. for i in {1..10}; do echo $i; done

B. for i in [1..10]; do echo $i; done

C. for i in (1..10); do echo $i; done

D. for i in <1..10>; do echo $i; done

Solution

1. Step 1: Identify correct brace expansion syntax

   Bash uses curly braces {start..end} for ranges, so {1..10} is correct.

2. Step 2: Check other options for syntax errors

   Parentheses, square brackets, and angle brackets are invalid for this purpose in Bash loops.

3. Final Answer:

   for i in {1..10}; do echo $i; done -> Option A

4. Quick Check:

   Brace expansion uses curly braces {..} [OK]

Hint: Use curly braces {start..end} for ranges in Bash loops [OK]

Common Mistakes:

• Using parentheses or brackets instead of braces
• Missing the 'in' keyword
• Forgetting to close the loop with 'done'

3. What is the output of this script?

for i in {3..6}; do echo $((i * 2)); done

medium

A. 2 4 6 8

B. 3 4 5 6

C. 6
8
10
12

D. Error: invalid arithmetic

Solution

1. Step 1: Identify loop values

   The loop variable i takes values 3, 4, 5, 6 from {3..6}.

2. Step 2: Calculate output for each iteration

   Each iteration prints i * 2: 3*2=6, 4*2=8, 5*2=10, 6*2=12.

3. Final Answer:

   6 8 10 12 -> Option C

4. Quick Check:

   Multiply each i by 2 [OK]

Hint: Multiply loop variable inside $(( )) for arithmetic [OK]

Common Mistakes:

• Confusing loop values with output
• Using single parentheses instead of $(( ))
• Expecting space-separated output on one line

4. Find the error in this Bash loop:

for i in {1..5} do
echo $i
done

medium

A. Variable $i is not defined

B. Loop body must be on the same line as for

C. Brace expansion syntax is wrong

D. Missing semicolon or newline after {1..5}

Solution

1. Step 1: Check for syntax correctness in loop header

   The for loop header must end with a semicolon or newline before 'do'. Here, 'do' follows directly after {1..5} without either, causing a syntax error.

2. Step 2: Verify other parts

   Variable $i is defined by the loop, brace syntax is correct, and loop body can be on next lines.

3. Final Answer:

   Missing semicolon or newline after {1..5} -> Option D

4. Quick Check:

   Loop header must end properly before 'do' [OK]

Hint: Put semicolon or newline before 'do' in for loops [OK]

Common Mistakes:

• Omitting semicolon or newline before 'do'
• Misunderstanding brace expansion syntax
• Thinking loop body must be on same line

5. You want to print only even numbers from 2 to 10 using a Bash for loop with brace expansion. Which script achieves this?

hard

A. for i in {2..10..2}; do echo $i; done

B. for i in {1..10}; do if [ $i % 2 == 0 ]; then echo $i; fi; done

C. for i in {2..10}; do echo $((i*2)); done

D. for i in {2..10..3}; do echo $i; done

Solution

1. Step 1: Understand brace expansion with step

   Brace expansion supports {start..end..step}, so {2..10..2} generates even numbers 2,4,6,8,10.

2. Step 2: Check other options

   B uses [ ] test which performs string comparison, not arithmetic modulo, so never prints evens; C multiplies numbers incorrectly to 4,6,8,10,12,14,16,18,20; D steps by 3, not 2.

3. Final Answer:

   for i in {2..10..2}; do echo $i; done -> Option A

4. Quick Check:

   Use {start..end..step} for stepped ranges [OK]

Hint: Use {start..end..step} to loop with steps in Bash [OK]

Common Mistakes:

• Not using step in brace expansion
• Multiplying loop variable instead of stepping
• Using wrong step size