Long option parsing in Bash Scripting - Mini Project: Build & Apply

Long Option Parsing in Bash Script

📖 Scenario: You are creating a simple bash script that accepts long options from the command line. This is common when you want your script to be user-friendly and clear, like many Linux commands.Imagine you want to make a script that accepts options like --name and --age to greet a user with their name and age.

🎯 Goal: Build a bash script that parses two long options --name and --age from the command line and prints a greeting message using those values.

📋 What You'll Learn

Create variables to hold the name and age

Use a while loop with a case statement to parse --name and --age options

Assign the values passed to these options to the variables

Print a greeting message using the parsed values

💡 Why This Matters

🌍 Real World

Parsing command line options is essential for making scripts user-friendly and flexible, just like many Linux commands you use daily.

💼 Career

Understanding how to parse options in bash scripts is a key skill for system administrators, DevOps engineers, and anyone automating tasks on Linux servers.

1

Create variables to hold name and age

Create two variables called name and age and set both to empty strings.

Bash Scripting

# Create variables 'name' and 'age' and set them to empty strings
# Your code here

Need a hint?

Use name="" and age="" to create empty string variables.

2

Set up a while loop to parse command line arguments

Add a while loop that runs while [[ $# -gt 0 ]] to process all command line arguments. Inside the loop, use a case statement on $1 to check for --name and --age options.

Bash Scripting

name=""
age=""

# Add a while loop to process command line arguments
# Your code here

Need a hint?

Use while [[ $# -gt 0 ]] and case "$1" in to check options.

3

Assign values to name and age inside the case

Inside the case statement, for --name assign the next argument $2 to name and shift twice. For --age, assign $2 to age and shift twice.

Bash Scripting

name=""
age=""

while [[ $# -gt 0 ]]; do
    case "$1" in
        --name)
            # Assign $2 to name and shift twice
            # Your code here
            ;;
        --age)
            # Assign $2 to age and shift twice
            # Your code here
            ;;
        *)
            echo "Unknown option: $1"
            exit 1
            ;;
    esac
    shift
 done

Need a hint?

Use name="$2" and shift 2 to assign and move to next arguments.

4

Print the greeting message using parsed name and age

Add a echo statement after the loop to print: Hello, NAME! You are AGE years old. replacing NAME and AGE with the variables name and age.

Bash Scripting

name=""
age=""

while [[ $# -gt 0 ]]; do
    case "$1" in
        --name)
            name="$2"
            shift 2
            continue
            ;;
        --age)
            age="$2"
            shift 2
            continue
            ;;
        *)
            echo "Unknown option: $1"
            exit 1
            ;;
    esac
    shift
 done

# Print greeting message
# Your code here

Need a hint?

Use echo "Hello, $name! You are $age years old." to print the message.