Style guide and conventions in Bash Scripting - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of this script regarding variable naming?

Consider this bash script snippet that follows common style conventions for variable names. What will be the output?

Bash Scripting

MY_VAR=5
my_var=10
echo "$MY_VAR $my_var"

A 5 10

B 10 5

C MY_VAR my_var

D 5 5

💡 Hint

Variable names in bash are case-sensitive.

In bash, variable names are case-sensitive. MY_VAR and my_var are two different variables. MY_VAR is assigned 5, my_var is assigned 10, so echo prints '5 10'.

📝 Syntax

intermediate

Which option correctly follows the style guide for function definitions in bash?

Select the function definition that follows common bash style conventions for readability and compatibility.

A

function myFunc() {
  echo "Hello"
}

B

function myFunc {
  echo "Hello"
}

C

myFunc ()
{
  echo "Hello"
}

D

myFunc() {
  echo "Hello"
}

💡 Hint

The preferred style avoids the 'function' keyword and places parentheses immediately after the function name.

The recommended style for bash functions is 'name() { ... }' without the 'function' keyword for better portability and clarity.

🔧 Debug

advanced

Identify the style violation causing the script to fail in strict mode

This script fails when run with 'set -u' (treat unset variables as errors). What style issue causes this failure?

Bash Scripting

echo "User: $USER_NAME"
if [ "$USER_NAME" = "admin" ]; then
  echo "Welcome admin"
fi

A USER_NAME is used without being initialized, violating style to always initialize variables.

B The if statement uses single brackets instead of double brackets.

C The echo command lacks quotes around the variable.

D The script uses uppercase variable names which is discouraged.

💡 Hint

Strict mode requires variables to be initialized before use.

Using 'set -u' causes an error if a variable is used before being set. The style guide recommends initializing variables to avoid this error.

🧠 Conceptual

advanced

Why is it recommended to use lowercase variable names for local variables in bash scripts?

Choose the best explanation for why local variables in bash scripts are often named in lowercase.

A Lowercase variables are easier to type on the keyboard.

B Lowercase variables avoid conflicts with environment variables which are usually uppercase.

C Lowercase variables are automatically exported to child processes.

D Lowercase variables run faster in bash scripts.

💡 Hint

Think about environment variables and naming conventions.

Environment variables and system variables are usually uppercase. Using lowercase for local variables avoids accidental overwriting and confusion.

🚀 Application

expert

What is the output of this script following style conventions for quoting and command substitution?

Analyze the script and select the correct output. The script uses recommended style for quoting and command substitution.

Bash Scripting

files_count=$(ls -1 | wc -l)
echo "Number of files: $files_count"

A Number of files: ls -1 | wc -l

B Number of files: $(ls -1 | wc -l)

C Number of files: 3

D Number of files:

💡 Hint

Command substitution captures the output of the command inside $(...).

The command substitution $(ls -1 | wc -l) runs the commands and stores the output (number of files) in files_count. The echo prints the number.