Calling functions in Bash Scripting - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to call the function named greet.

Bash Scripting

greet() {
  echo "Hello!"
}

[1]

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

Agreet()

Bcall greet

Crun greet

Dgreet

Attempts:

3 left

💡 Hint

Common Mistakes

Using parentheses when calling the function causes errors.

Trying to use 'call' or 'run' commands which don't exist in bash.

In bash, to call a function, just write its name without parentheses.

2fill in blank

medium

Complete the code to call the function say_hello with an argument.

Bash Scripting

say_hello() {
  echo "Hello, $1!"
}

[1]

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

Asay_hello(John)

Bsay_hello John

Csay_hello

Dcall say_hello John

Attempts:

3 left

💡 Hint

Common Mistakes

Using parentheses around arguments like in other languages.

Trying to use 'call' keyword which is not valid in bash.

To pass an argument to a bash function, write the function name followed by the argument separated by space.

3fill in blank

hard

Fix the error in calling the function print_date correctly.

Bash Scripting

print_date() {
  date
}

[1]

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

Aprint_date {}

Bprint_date()

Cprint_date

Dcall print_date

Attempts:

3 left

💡 Hint

Common Mistakes

Adding parentheses when calling the function.

Using 'call' keyword which is invalid in bash.

Calling a bash function requires only its name without parentheses or extra keywords.

4fill in blank

hard

Fill both blanks to call the function greet_user with the argument 'Alice'.

Bash Scripting

greet_user() {
  echo "Welcome, $1!"
}

[1] [2]

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

Agreet_user

BAlice

C'Alice'

Dgreet_user()

Attempts:

3 left

💡 Hint

Common Mistakes

Using parentheses when calling the function.

Adding quotes around the argument which are not needed.

Call the function by its name followed by the argument without quotes.

5fill in blank

hard

Fill all three blanks to call the function calculate_sum with two numbers and store the result.

Bash Scripting

calculate_sum() {
  echo $(($1 + $2))
}

result=$([1] [2] [3])

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

Acalculate_sum

B5

C7

Dcalculate_sum()

Attempts:

3 left

💡 Hint

Common Mistakes

Using parentheses in the function call.

Not separating the arguments with spaces.

Trying to call the function without command substitution.

Call the function by its name followed by two arguments separated by spaces inside the command substitution.

Practice

1. In Bash scripting, how do you call a function named greet?

easy

A. Write greet() with parentheses.

B. Write call greet().

C. Just write greet on a line by itself.

D. Write run greet.

Solution

1. Step 1: Understand Bash function call syntax

   In Bash, functions are called by simply writing their name without parentheses or keywords.

2. Step 2: Compare options with Bash syntax

   Only Just write greet on a line by itself. matches the correct way: just the function name alone.

3. Final Answer:

   Just write greet on a line by itself. -> Option C

4. Quick Check:

   Function call = function name alone [OK]

Hint: Call functions by name only, no parentheses needed [OK]

Common Mistakes:

• Adding parentheses like in other languages
• Using keywords like 'call' or 'run'
• Forgetting to write the function name

2. Which of the following is the correct syntax to define a function named hello in Bash?

easy

A. hello { echo "Hi" }

B. hello() { echo "Hi" }

C. def hello() { echo "Hi" }

D. function hello() echo "Hi"

Solution

1. Step 1: Recall Bash function definition syntax

   Bash functions are defined as name() { commands; } or with the keyword function followed by name and braces.

2. Step 2: Check each option

   hello() { echo "Hi" } uses hello() { echo "Hi" }, which is correct. hello { echo "Hi" } misses the () after the name. def hello() { echo "Hi" } uses Python syntax. function hello() echo "Hi" misses braces.

3. Final Answer:

   hello() { echo "Hi" } -> Option B

4. Quick Check:

   Function syntax = name() { commands } [OK]

Hint: Use name() { commands } to define functions in Bash [OK]

Common Mistakes:

• Using Python or other language syntax
• Omitting parentheses or braces
• Misplacing the function keyword

3. What is the output of this script?

say_hello() {
  echo "Hello, $1!"
}
say_hello Alice

medium

A. Hello, Alice!

B. Hello, $1!

C. say_hello Alice

D. Error: function not found

Solution

1. Step 1: Understand function and argument usage

   The function say_hello prints "Hello," followed by the first argument $1.

2. Step 2: Identify the argument passed

   The function is called with argument "Alice", so $1 becomes "Alice".

3. Final Answer:

   Hello, Alice! -> Option A

4. Quick Check:

   Function argument $1 = Alice [OK]

Hint: Use $1 to access first argument inside function [OK]

Common Mistakes:

• Printing literal $1 instead of its value
• Forgetting to pass argument
• Misunderstanding function call syntax

4. Identify the error in this script:

greet() {
  echo "Hi $name"
}
greet John

medium

A. Function greet is not defined correctly

B. Missing semicolon after echo

C. Function call syntax is wrong

D. Variable $name is not set or passed

Solution

1. Step 1: Check variable usage inside function

   The function uses $name, but no variable named name is set or passed.

2. Step 2: Check function call and argument passing

   The function is called with "John" as argument, but the function does not use $1 to access it.

3. Final Answer:

   Variable $name is not set or passed -> Option D

4. Quick Check:

   Use $1 to access arguments, not undefined variables [OK]

Hint: Use $1 inside function to get passed arguments [OK]

Common Mistakes:

• Using undefined variables instead of $1
• Assuming arguments auto-assign to variable names
• Ignoring function call syntax correctness

5. You want to write a Bash function sum that takes two numbers as arguments and prints their sum. Which script correctly calls the function and prints the result?

hard

A. sum() {
echo $(($1 + $2))
}
sum 3 5

B. sum() {
echo $1 + $2
}
sum 3 5

C. sum() {
echo $((1 + 2))
}
sum 3 5

D. sum() {
echo $1 $2
}
sum 3 5

Solution

1. Step 1: Understand arithmetic evaluation in Bash

   To add numbers, use $((expression)). Inside, use $1 and $2 for arguments.

2. Step 2: Check each option's output

   sum() {
     echo $(($1 + $2))
   }
   sum 3 5

   correctly sums $1 + $2.

   sum() {
     echo $1 + $2
   }
   sum 3 5

   prints literal string with plus sign.

   sum() {
     echo $((1 + 2))
   }
   sum 3 5

   adds 1 and 2 literally, ignoring arguments.

   sum() {
     echo $1 $2
   }
   sum 3 5

   prints arguments separated by space.

3. Final Answer:

   sum() { echo $(($1 + $2)) } sum 3 5 -> Option A

4. Quick Check:

   Use $(( $1 + $2 )) for sum [OK]

Hint: Use $(( $1 + $2 )) to add arguments inside function [OK]

Common Mistakes:

• Printing arguments without arithmetic evaluation
• Using fixed numbers instead of arguments
• Confusing string concatenation with addition