Why file I/O is core to scripting in Bash Scripting - See It in Action

Why file I/O is core to scripting

📖 Scenario: You work as a helper for a small shop. The shop keeps a list of products and their prices in a text file. You want to write a script that reads this file, finds products that cost more than a certain amount, and saves those products to a new file. This helps the shop owner quickly see expensive items.

🎯 Goal: Build a bash script that reads a file with product prices, filters products above a price limit, and writes them to a new file.

📋 What You'll Learn

Create a file named products.txt with exact product and price lines

Create a variable price_limit with a specific value

Use a while loop to read products.txt line by line

Write products with price greater than price_limit to expensive.txt

Print the contents of expensive.txt at the end

💡 Why This Matters

🌍 Real World

Scripts often read and write files to automate tasks like filtering logs, processing data, or generating reports.

💼 Career

Knowing file input/output is essential for automation roles, system administration, and any scripting job to handle real data.

1

Create the product list file

Create a file named products.txt with these exact lines:
Apple 50
Banana 20
Cherry 75
Date 30
Elderberry 90

Bash Scripting

# Create the file products.txt with the exact lines
# Your code here

Need a hint?

Use cat with a here-document to create the file with exact lines.

2

Set the price limit variable

Create a variable called price_limit and set it to 40.

Bash Scripting

cat  products.txt
Apple 50
Banana 20
Cherry 75
Date 30
Elderberry 90
EOF

# Set price_limit to 40
# Your code here

Need a hint?

Use price_limit=40 to set the variable.

3

Filter products above the price limit

Use a while loop with read to read products.txt line by line. For each line, split into product and price. If price is greater than price_limit, append the line to a file named expensive.txt. Clear expensive.txt before the loop starts.

Bash Scripting

cat  products.txt
Apple 50
Banana 20
Cherry 75
Date 30
Elderberry 90
EOF

price_limit=40

# Clear expensive.txt
# Use while read loop to filter and save products
# Your code here

Need a hint?

Use while read product price; do ... done < products.txt and test price with [ "$price" -gt "$price_limit" ].

4

Display the filtered products

Print the contents of expensive.txt using cat.

Bash Scripting

cat expensive.txt
# Your code here

Need a hint?

Use cat expensive.txt to show the filtered products.