sed for substitution in scripts in Bash Scripting - Mini Project: Build & Apply

Using sed for Substitution in Scripts

📖 Scenario: You are working on a script that processes a text file containing product names and prices. You want to update the prices by increasing them by 10% using sed substitution commands.

🎯 Goal: Build a bash script that uses sed to substitute old prices with new prices in a text file.

📋 What You'll Learn

Create a text file variable with product names and prices

Create a variable for the price increase percentage

Use sed substitution to update prices by 10%

Print the updated text to the terminal

💡 Why This Matters

🌍 Real World

Automating price updates in product lists or configuration files without manual editing.

💼 Career

Many automation and scripting jobs require text processing and substitution using tools like sed.

1

Create the initial product list

Create a variable called products that contains these exact lines as a multiline string:
Apple 100
Banana 50
Cherry 75

Bash Scripting

# Create a variable called products with the exact lines
# Your code here

Need a hint?

Use double quotes and \n for new lines inside the string.

2

Set the price increase percentage

Create a variable called increase and set it to 10 to represent a 10% price increase.

Bash Scripting

products="Apple 100\nBanana 50\nCherry 75"
# Create a variable called increase and set it to 10
# Your code here

Need a hint?

Just assign the number 10 to the variable increase.

3

Use sed to increase prices by 10%

Use a sed command to substitute each price in products by increasing it by 10%. Use the echo command to pass products to sed. Store the result in a variable called updated_products. Use this exact sed expression: sed -E 's/([0-9]+)/echo $((\1 * 110 / 100))/ge'

Bash Scripting

products="Apple 100\nBanana 50\nCherry 75"
increase=10
# Use sed with echo and arithmetic expansion to increase prices by 10%
# Store the output in updated_products
# Your code here

Need a hint?

The sed command uses s/([0-9]+)/echo $((\1 * 110 / 100))/ge to replace each number with the increased price.

4

Print the updated product list

Print the variable updated_products to display the updated product names and prices.

Bash Scripting

products="Apple 100\nBanana 50\nCherry 75"
increase=10
updated_products=$(echo "$products" | sed -E 's/([0-9]+)/echo $((\1 * 110 / 100))/ge')
# Print updated_products
# Your code here

Need a hint?

Use echo "$updated_products" to print the updated list.