if-then-else in Bash Scripting - Mini Project: Build & Apply

Basic Decision Making with if-then-else in Bash

📖 Scenario: You are writing a simple script to check if a number is positive, negative, or zero. This is like checking the weather and deciding what to wear: if it's hot, wear shorts; if cold, wear a jacket; else wear something in between.

🎯 Goal: Build a bash script that uses if-then-else statements to print whether a number is positive, negative, or zero.

📋 What You'll Learn

Create a variable number with the value 5

Create a variable zero with the value 0

Use if, elif, and else to check if number is greater than, less than, or equal to zero

Print exactly Positive, Negative, or Zero based on the check

💡 Why This Matters

🌍 Real World

Scripts often need to make decisions based on input values, like checking if a file exists or if a user is logged in.

💼 Career

Understanding if-then-else logic is essential for automating tasks, writing installation scripts, and managing system operations.

1

Set the number variable

Create a variable called number and set it to 5.

Bash Scripting

# Your code here

Need a hint?

Use variable=value syntax without spaces in bash.

2

Set the zero variable

Create a variable called zero and set it to 0.

Bash Scripting

number=5
# Your code here

Need a hint?

Remember no spaces around the equals sign.

3

Write the if-then-else logic

Write an if statement to check if number is greater than zero using [ $number -gt $zero ]. Then use elif to check if number is less than zero using [ $number -lt $zero ]. Use else for the case when number equals zero. Inside each block, use echo to print Positive, Negative, or Zero respectively.

Bash Scripting

number=5
zero=0
# Your code here

Need a hint?

Use if [ condition ]; then ... elif [ condition ]; then ... else ... fi structure.

4

Run the script to see the output

Run the script and print the output. The output should be exactly Positive.

Bash Scripting

number=5
zero=0
if [ $number -gt $zero ]; then
    echo Positive
elif [ $number -lt $zero ]; then
    echo Negative
else
    echo Zero
fi
# Your code here

Need a hint?

Run the script in a terminal or use bash script.sh if saved in a file.