awk patterns and actions in Linux CLI - Mini Project: Build & Apply

Learn awk Patterns and Actions

📖 Scenario: You have a small text file listing fruits and their quantities. You want to use awk to find and display fruits with quantities greater than a certain number.

🎯 Goal: Build an awk command that filters and prints fruits with quantities above a threshold.

📋 What You'll Learn

Create a text file named fruits.txt with exact content

Define a variable threshold with a numeric value

Write an awk command using a pattern to filter lines where quantity is greater than threshold

Print the fruit name and quantity for matching lines

💡 Why This Matters

🌍 Real World

Filtering and processing text data files is common in system administration and data analysis.

💼 Career

Knowing how to use awk patterns and actions helps automate log analysis, report generation, and data extraction tasks.

1

Create the data file fruits.txt

Create a file named fruits.txt with these exact lines:
apple 10
banana 5
cherry 12
date 7
elderberry 3

Linux CLI

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

Need a hint?

Use echo with -e and redirect output to fruits.txt.

2

Set the quantity threshold variable

Create a shell variable named threshold and set it to 6

Linux CLI

echo -e "apple 10\nbanana 5\ncherry 12\ndate 7\nelderberry 3" > fruits.txt
# Set the variable threshold to 6
# Your code here

Need a hint?

Use threshold=6 to set the variable.

3

Write the awk command with pattern and action

Write an awk command that reads fruits.txt and prints the fruit name and quantity only if the quantity (second column) is greater than the shell variable threshold. Use the pattern $2 > threshold and print both fields.

Linux CLI

echo -e "apple 10\nbanana 5\ncherry 12\ndate 7\nelderberry 3" > fruits.txt
threshold=6
# Write the awk command below
# Your code here

Need a hint?

Use awk -v threshold="$threshold" '$2 > threshold {print $1, $2}' fruits.txt.

4

Run the awk command and display output

Run the awk command from Step 3 and print the output showing fruits with quantity greater than threshold.

Linux CLI

echo -e "apple 10\nbanana 5\ncherry 12\ndate 7\nelderberry 3" > fruits.txt
threshold=6
awk -v threshold="$threshold" '$2 > threshold {print $1, $2}' fruits.txt
# Run the command and print output
# Your code here

Need a hint?

The output should list fruits with quantities above 6.