Return values (return and echo) in Bash Scripting - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to return the value 5 from the function.

Bash Scripting

my_func() {
  [1] 5
}
my_func

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

Aprint

Becho

Creturn

Dexit

Attempts:

3 left

💡 Hint

Common Mistakes

Using echo instead of return to send back a value.

Using exit inside the function which stops the whole script.

The return command in bash functions sets the exit status (an integer between 0 and 255). Here, return 5 returns the value 5 as the function's exit status.

2fill in blank

medium

Complete the code to print the string 'Hello' from the function.

Bash Scripting

greet() {
  [1] "Hello"
}
greet

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

Aecho

Bprint

Cexit

Dreturn

Attempts:

3 left

💡 Hint

Common Mistakes

Using return to try to print text.

Using print which is not a bash command.

The echo command prints text to the terminal. Here, echo "Hello" prints the string 'Hello' when the function is called.

3fill in blank

hard

Fix the error in the function to correctly return the exit status 3.

Bash Scripting

check_status() {
  [1] 3
}
check_status
status=$?
echo $status

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

Aecho

Bprint

Cexit

Dreturn

Attempts:

3 left

💡 Hint

Common Mistakes

Using echo instead of return to set exit status.

Using exit which terminates the script.

To set the function's exit status, use return. Using echo prints the number but does not set the exit status. The variable $? captures the exit status.

4fill in blank

hard

Fill both blanks to create a function that prints 'Done' and returns exit status 0.

Bash Scripting

finish() {
  [1] "Done"
  [2] 0
}
finish
status=$?
echo $status

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

Aecho

Bexit

Creturn

Dprint

Attempts:

3 left

💡 Hint

Common Mistakes

Using exit instead of return which stops the script.

Using print which is not a bash command.

The function uses echo to print 'Done' and return 0 to set the exit status to 0, indicating success.

5fill in blank

hard

Fill all three blanks to create a function that prints the argument, returns 1 if argument is 'fail', else returns 0.

Bash Scripting

result() {
  [1] "$1"
  if [[ "$1" == "fail" ]]; then
    [2] 1
  else
    [3] 0
  fi
}
result "$1"
exit_status=$?
echo $exit_status

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

Aecho

Breturn

Cexit

Dprint

Attempts:

3 left

💡 Hint

Common Mistakes

Using exit inside the function which stops the whole script.

Using print which is not a bash command.

Using echo instead of return to set exit status.

The function prints the argument with echo. It uses return 1 if the argument is 'fail', otherwise return 0. This sets the function's exit status correctly.

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