dmesg for kernel messages in Linux CLI - Mini Project: Build & Apply

Using dmesg to View Kernel Messages

📖 Scenario: You are a system administrator who wants to check the system's kernel messages to troubleshoot hardware or driver issues.

🎯 Goal: Learn how to use the dmesg command to view kernel messages and filter them by keywords.

📋 What You'll Learn

Use the dmesg command to display kernel messages

Create a variable to store the output of dmesg

Filter kernel messages containing the word usb

Print the filtered messages

💡 Why This Matters

🌍 Real World

System administrators often need to check kernel messages to diagnose hardware or driver problems on Linux servers or desktops.

💼 Career

Knowing how to use <code>dmesg</code> and filter its output is a basic skill for Linux system troubleshooting and monitoring.

1

Capture Kernel Messages

Run the command dmesg and save its output to a variable called kernel_messages.

Linux CLI

# Run dmesg and save output to kernel_messages
# Your code here

Need a hint?

Use command substitution with $( ) to save the output of dmesg into a variable.

2

Set Filter Keyword

Create a variable called filter_keyword and set it to the string usb.

Linux CLI

kernel_messages=$(dmesg)
# Set filter_keyword to 'usb'
# Your code here

Need a hint?

Assign the string usb to the variable filter_keyword using double quotes.

3

Filter Kernel Messages

Use grep with the variable filter_keyword to filter kernel_messages and save the result to a variable called filtered_messages.

Linux CLI

kernel_messages=$(dmesg)
filter_keyword="usb"
# Filter kernel_messages by filter_keyword and save to filtered_messages
# Your code here

Need a hint?

Use echo to send kernel_messages to grep and save the output.

4

Display Filtered Messages

Print the contents of the variable filtered_messages to display the filtered kernel messages.

Linux CLI

kernel_messages=$(dmesg)
filter_keyword="usb"
filtered_messages=$(echo "$kernel_messages" | grep "$filter_keyword")
# Print filtered_messages
# Your code here

Need a hint?

Use echo to print the variable filtered_messages.