Function definition in Bash Scripting - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Output of a simple Bash function call

What is the output of this Bash script?

Bash Scripting

greet() {
  echo "Hello, $1!"
}
greet World

A Hello, World!

B greet World

C Hello, $1!

D World

💡 Hint

Look at how the function uses the first argument $1 inside echo.

The function greet takes the first argument and prints it with Hello. Calling greet World passes 'World' as $1, so output is 'Hello, World!'.

💻 Command Output

intermediate

Return value from a Bash function

What is the output of this Bash script?

Bash Scripting

add() {
  echo $(( $1 + $2 ))
}
result=$(add 3 4)
echo $result

A 34

B add 3 4

C 3 4

D 7

💡 Hint

The function echoes the sum of two numbers, which is captured in result.

The add function calculates the sum of $1 and $2 and echoes it. The output is captured in 'result' and then printed, so the output is 7.

📝 Syntax

advanced

Identify the syntax error in this Bash function

Which option contains the correct syntax for defining a Bash function?

A greet() { echo "Hi" }

B greet() echo "Hi"

C function greet() { echo "Hi" }

D function greet { echo "Hi" }

💡 Hint

A Bash function needs parentheses and braces properly placed.

Options A and C use correct syntax: function name with parentheses followed by braces enclosing the commands. Option D is also valid in Bash but less common.

🔧 Debug

advanced

Why does this Bash function not print the expected output?

Given this script, what is the reason it prints nothing? myfunc() { local msg="Hello" } myfunc echo $msg

A The variable msg is local to the function and not visible outside.

B The function myfunc is never called.

C The echo command is inside the function but not executed.

D The variable msg is misspelled.

💡 Hint

Think about variable scope inside and outside functions.

The variable msg is declared local inside the function, so it does not exist outside. The echo command outside prints an empty value.

🚀 Application

expert

Function to check if a file exists and is readable

Which function definition correctly checks if a file exists and is readable, then prints 'File OK' or 'File missing or unreadable'?

A

check_file() {
  if [[ -r "$1" ]]; then
    echo "File OK"
  else
    echo "File missing or unreadable"
  fi
}

B

check_file() {
  if test -r "$1"; then
    echo "File OK"
  else
    echo "File missing or unreadable"
  fi
}

C

check_file() {
  if [ -f "$1" -a -r "$1" ]; then
    echo "File OK"
  else
    echo "File missing or unreadable"
  fi
}

D

check_file() {
  if [ -e "$1" ] && [ -r "$1" ]; then
    echo "File OK"
  else
    echo "File missing or unreadable"
  fi
}

💡 Hint

Check both if the file exists and is readable using test operators.

Option C uses [ -f "$1" -a -r "$1" ] which checks if the file exists and is a regular file and readable. This is the most precise check.