Return values (return and echo) in Bash Scripting - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of this Bash function call?

Consider the following Bash script. What will be printed when the function is called?

Bash Scripting

myfunc() {
  echo "Hello"
  return 5
}
myfunc
echo $?  # prints the return value of the function

A Hello\n5

B 5\nHello

C Hello

D 5

💡 Hint

Remember that echo prints to standard output, and return sets the exit status.

The function prints "Hello" first. Then the return 5 sets the exit status to 5. The echo $? prints that exit status after the function call.

💻 Command Output

intermediate

What does this script output?

What is the output of this Bash script?

Bash Scripting

func() {
  local val=10
  echo $val
  return 3
}
result=$(func)
echo "$result"
echo $?  # exit status of func

A 3\n10

B 10\n3

C 10\n0

D 3\n0

💡 Hint

Check what is captured by command substitution and what is the exit status.

The command substitution captures the echo output "10". The return 3 sets the exit status. echo $? prints 3.

📝 Syntax

advanced

Which option causes a syntax error in a Bash function?

Which of these function definitions will cause a syntax error?

A myfunc() { echo "Hi"; return 1; }

B myfunc() { echo "Hi"; return 1 }

C } ;1 nruter ;"iH" ohce { )(cnufym

D myfunc() { echo "Hi" return 1; }

💡 Hint

Look for missing semicolons or command separators.

Option D misses a semicolon or newline between echo and return, causing syntax error.

🚀 Application

advanced

How to capture both output and return code from a Bash function?

You want to capture the output of a Bash function and also check its return code. Which snippet does this correctly?

A

output=$(myfunc; ret=$?)
echo "$output"
echo $ret

B

ret=$(myfunc)
output=$?
echo "$output"
echo $ret

C

output=$(myfunc)
ret=$?
echo "$output"
echo $ret

D

output=myfunc
ret=$?
echo "$output"
echo $ret

💡 Hint

Remember that $? holds the exit status of the last command.

Option C correctly captures output with $(myfunc) and then saves the exit status with ret=$?.

🧠 Conceptual

expert

What is the difference between return and echo in Bash functions?

Which statement best describes the difference between return and echo in Bash functions?

A "return" sets the function's exit status, "echo" prints text to standard output.

B "return" sends a value to the caller as output, "echo" sets the function's exit status.

C "return" prints text to standard output, "echo" sets the function's exit status.

D "return" and "echo" both print text but differ in syntax.

💡 Hint

Think about what return and echo do in a shell script.

In Bash, return sets the exit status (a number 0-255), echo prints text to the screen or output stream.

Practice

1. In bash scripting, what does the return command inside a function do?

easy

A. It stops the entire script immediately.

B. It sends a numeric status code back to the caller.

C. It prints text output to the terminal.

D. It saves the function output to a file.

Solution

1. Step 1: Understand the purpose of return in bash functions

   The return command sends a numeric exit status (0-255) back to the caller, indicating success or failure.

2. Step 2: Differentiate from echo

   Unlike echo, which prints text output, return only sends a number status, not text.

3. Final Answer:

   It sends a numeric status code back to the caller. -> Option B

4. Quick Check:

   return = numeric status [OK]

Hint: Remember: return sends number status, echo prints text [OK]

Common Mistakes:

• Thinking return prints output like echo
• Using return to output strings
• Confusing return with exit

2. Which of the following is the correct syntax to return a status code 5 from a bash function named check?

easy

A. exit 5

B. echo 5

C. return(status=5)

D. return 5

Solution

1. Step 1: Recall bash function return syntax

   To return a status code from a function, use return followed by the number, e.g., return 5.

2. Step 2: Identify incorrect options

   echo 5 prints text, return(status=5) is invalid syntax, and exit 5 exits the whole script.

3. Final Answer:

   return 5 -> Option D

4. Quick Check:

   Use return number syntax [OK]

Hint: Use 'return' followed by number to send status [OK]

Common Mistakes:

• Using echo instead of return for status
• Trying to use parentheses in return
• Using exit inside function to return status

3. What will be the output of this script?

myfunc() {
  echo "Hello"
  return 3
}
myfunc
echo $? 

medium

A. 3\nHello

B. Hello\n0

C. Hello\n3

D. 3\n3

Solution

1. Step 1: Analyze function output

   The function prints "Hello" using echo, so "Hello" appears first.

2. Step 2: Check return status and echo it

   The function returns 3, so $? after calling it is 3, which is printed next.

3. Final Answer:

   Hello\n3 -> Option C

4. Quick Check:

   echo prints text, return sets status [OK]

Hint: echo prints text first, $? shows return code after function [OK]

Common Mistakes:

• Confusing echo output with return value
• Expecting return value to print automatically
• Ignoring that $? holds last return status

4. Identify the error in this bash function:

myfunc() {
  return "Success"
}
myfunc
echo $?

medium

A. return expects a number, not a string

B. echo cannot print return values

C. Function missing parentheses

D. return must be last command in function

Solution

1. Step 1: Understand return command rules

   In bash, return must be followed by a numeric status (0-255), not a string.

2. Step 2: Identify the error in the code

   The code tries to return "Success" (a string), which causes an error.

3. Final Answer:

   return expects a number, not a string -> Option A

4. Quick Check:

   return only accepts numbers [OK]

Hint: return only accepts numbers, not text [OK]

Common Mistakes:

• Trying to return strings with return
• Confusing echo and return usage
• Assuming return prints output

5. How can you capture the text output of a bash function greet that uses echo inside, and store it in a variable msg?

hard

A. msg=$(greet)

B. msg=return greet

C. msg=`return greet`

D. msg=echo greet

Solution

1. Step 1: Understand capturing function output

   To capture text output from a function that uses echo, use command substitution: $(function_name).

2. Step 2: Identify correct syntax

   msg=$(greet) runs greet and stores its echo output in msg. Other options misuse return or echo.

3. Final Answer:

   msg=$(greet) -> Option A

4. Quick Check:

   Use $(function) to capture echo output [OK]

Hint: Use $(function) to capture echo output in variable [OK]

Common Mistakes:

• Using return instead of command substitution
• Assigning echo command directly to variable
• Using backticks incorrectly with return