String variables in Bash Scripting - Mini Project: Build & Apply

String variables

📖 Scenario: You are writing a simple bash script to store and display a greeting message. This is like writing a note to yourself that you want to see later.

🎯 Goal: Create a string variable in bash, assign a greeting message to it, and then print it to the screen.

📋 What You'll Learn

Create a string variable named greeting with the exact value Hello, welcome to bash scripting!

Create a variable named name with the exact value Friend

Use string concatenation to create a new variable personal_greeting that combines greeting and name with a space in between

Print the value of personal_greeting to the screen

💡 Why This Matters

🌍 Real World

Storing and manipulating text messages in scripts is common for creating user prompts, logs, and notifications.

💼 Career

Understanding string variables is a basic skill for writing shell scripts that automate tasks and communicate with users.

1

Create a string variable

Create a string variable called greeting and assign it the exact value Hello, welcome to bash scripting!

Bash Scripting

# Create the greeting variable with the exact text
# Your code here

Hint

Use the syntax variable_name="value" to create a string variable in bash.

2

Add a name variable

Create a string variable called name and assign it the exact value Friend

Bash Scripting

greeting="Hello, welcome to bash scripting!"
# Create the name variable with the exact text
# Your code here

Hint

Remember to use double quotes around the string value.

3

Combine strings into a new variable

Create a new variable called personal_greeting that combines greeting and name with a space between them using string concatenation

Bash Scripting

greeting="Hello, welcome to bash scripting!"
name="Friend"
# Combine greeting and name into personal_greeting with a space
# Your code here

Hint

Use variable="$var1 $var2" to join strings with a space in bash.

4

Print the combined greeting

Print the value of the variable personal_greeting to the screen using echo

Bash Scripting

greeting="Hello, welcome to bash scripting!"
name="Friend"
personal_greeting="$greeting $name"
# Print personal_greeting
# Your code here

Hint

Use echo "$variable" to print a variable's value in bash.

Practice

1. What is the correct way to assign the string Hello to a variable named greeting in bash?

easy

A. greeting="Hello"

B. greeting = "Hello"

C. greeting: "Hello"

D. greeting <- "Hello"

Solution

1. Step 1: Understand bash variable assignment syntax

   In bash, variable assignment must have no spaces around the equals sign.

2. Step 2: Check the options for correct syntax

   greeting="Hello" uses no spaces and quotes the string correctly. The other options have invalid syntax.

3. Final Answer:

   greeting="Hello" -> Option A

4. Quick Check:

   No spaces around = and quotes needed [OK]

Hint: No spaces around = and use quotes for strings [OK]

Common Mistakes:

• Adding spaces around = causes syntax errors
• Forgetting quotes around strings with spaces
• Using wrong assignment symbols like : or <-

2. Which of the following correctly prints the value of the variable name in bash?

easy

A. echo name

B. echo $name

C. echo &name

D. echo %name

Solution

1. Step 1: Recall how to access variable values in bash

   Use the dollar sign ($) before the variable name to get its value.

2. Step 2: Evaluate each option

   echo $name uses $name correctly. echo name prints the literal word 'name'. The other options use invalid symbols.

3. Final Answer:

   echo $name -> Option B

4. Quick Check:

   Use $ to access variable value [OK]

Hint: Use $ before variable to print its value [OK]

Common Mistakes:

• Forgetting $ prints variable name, not value
• Using wrong symbols like & or %
• Confusing variable access with assignment

3. What will be the output of this bash script?

name="Alice"
echo "Hello, $name!"

medium

A. Hello, Alice!

B. Hello, $name!

C. Hello, name!

D. Hello, !

Solution

1. Step 1: Understand variable assignment and usage

   The variable name is assigned the string "Alice".

2. Step 2: Analyze the echo command with variable expansion

   The echo command uses double quotes, so $name is replaced by its value "Alice".

3. Final Answer:

   Hello, Alice! -> Option A

4. Quick Check:

   Variables expand inside double quotes [OK]

Hint: Variables expand inside double quotes, not single quotes [OK]

Common Mistakes:

• Expecting variable expansion inside single quotes
• Printing variable name literally without $
• Forgetting to assign variable before use

4. Identify the error in this bash script:

message = "Hi there"
echo $message

medium

A. Variable name is invalid

B. Quotes should be single quotes

C. Missing $ before variable in echo

D. Spaces around = cause syntax error

Solution

1. Step 1: Check variable assignment syntax

   In bash, no spaces are allowed around the equals sign when assigning variables.

2. Step 2: Analyze the given script

   The line message = "Hi there" has spaces around =, causing a syntax error.

3. Final Answer:

   Spaces around = cause syntax error -> Option D

4. Quick Check:

   No spaces around = in assignments [OK]

Hint: No spaces around = in variable assignment [OK]

Common Mistakes:

• Adding spaces around =
• Using wrong quotes type causes no error here
• Forgetting $ in echo prints variable name literally

5. You want to store a user's full name with spaces in a variable fullname and then print it. Which script correctly does this?

hard

A. fullname=John Doe
echo $fullname

B. fullname='John Doe'
echo fullname

C. fullname="John Doe"
echo $fullname

D. fullname=John_Doe
echo $fullname

Solution

1. Step 1: Assign string with spaces to variable

   Strings with spaces must be quoted to be assigned correctly in bash.

2. Step 2: Print the variable value

   Use echo $fullname to print the stored string value.

3. Final Answer:

   fullname="John Doe" echo $fullname -> Option C

4. Quick Check:

   Quote strings with spaces and use $ to print [OK]

Hint: Quote strings with spaces; use $ to print variable [OK]

Common Mistakes:

• Not quoting strings with spaces causes errors
• Printing variable name without $ prints literal text
• Using underscores instead of spaces changes the string