Exit codes ($?) in Bash Scripting - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to print the exit code of the last command.

Bash Scripting

echo "Hello"; echo [1]

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

A$?

B$$

C$!

D$#

Attempts:

3 left

💡 Hint

Common Mistakes

Using $$ which gives the process ID instead of the exit code.

Using $! which gives the PID of the last background command.

Using $# which gives the number of positional parameters.

The special variable $? holds the exit code of the last executed command.

2fill in blank

medium

Complete the code to check if the last command succeeded (exit code 0).

Bash Scripting

some_command
if [ [1] -eq 0 ]; then echo "Success"; fi

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

A$$

B$?

C$!

D$#

Attempts:

3 left

💡 Hint

Common Mistakes

Using $$ which is the process ID, not the exit code.

Using $! which is the PID of the last background command.

Using $# which is the number of arguments.

The variable $? holds the exit code of the last command, which is 0 on success.

3fill in blank

hard

Fix the error in the code to correctly capture the exit code of a command.

Bash Scripting

ls /nonexistent_directory
exit_code=[1]
echo "Exit code: $exit_code"

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

A$?

B$#

C$!

D$$

Attempts:

3 left

💡 Hint

Common Mistakes

Using $$ which is the process ID, not the exit code.

Using $! which is the PID of the last background command.

Using $# which is the number of arguments.

The exit code of the last command is stored in $?. Assigning it to a variable captures it for later use.

4fill in blank

hard

Fill both blanks to create a script that runs a command and prints if it failed.

Bash Scripting

command_to_run
if [ [1] -ne 0 ]; then
  echo "Command failed with exit code [2]"
fi

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

A$?

B$$

D$#

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variables for the exit code in condition and echo.

Using $$ or $# which are not exit codes.

Use $? to check the exit code and also to print it. Both blanks need the exit code variable.

5fill in blank

hard

Fill all three blanks to save the exit code, check it, and print a message.

Bash Scripting

some_command
exit_code=[1]
if [ [2] -eq 0 ]; then
  echo "Command succeeded with code [3]"
fi

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

A$?

Bexit_code

D$$

Attempts:

3 left

💡 Hint

Common Mistakes

Using $? directly in the if after assigning it to a variable.

Using $$ which is the process ID.

Assign $? to exit_code, then check exit_code and print it. This saves and reuses the exit code.