Linux showkey Command with Practical Examples

Introduction

In this lab, we will explore the Linux showkey command and its practical applications. The showkey command is a utility that allows you to capture and display the key codes generated by your keyboard, which can be useful for troubleshooting keyboard-related issues or understanding how your keyboard communicates with the system. We will learn how to use the showkey command to capture keyboard input and analyze the output. This lab is designed to provide a hands-on understanding of the showkey command and its use cases.

Linux Commands Cheat Sheet

Understand the Purpose of the showkey Command

In this step, we will explore the purpose of the showkey command in Linux. The showkey command is a utility that allows you to capture and display the key codes generated by your keyboard. This can be useful for troubleshooting keyboard-related issues or understanding how your keyboard is communicating with the system.

To begin, let's start the showkey command in the terminal:

sudo showkey

Example output:

Press any keys - Ctrl-C to end
key pressed 1 is 65 (a)
key pressed 2 is 66 (b)
key pressed 3 is 67 (c)
^C

The showkey command will continue to run and display the key codes for every key you press on your keyboard. The output shows the decimal code for each key, as well as the corresponding character in parentheses.

The showkey command can be useful in several scenarios:

1. Troubleshooting keyboard issues: If you're experiencing problems with your keyboard, such as certain keys not working or unexpected behavior, the showkey command can help you identify the root cause by showing the key codes being generated.

2. Mapping custom keyboard shortcuts: If you want to create custom keyboard shortcuts or macros, the showkey output can help you determine the key codes to use in your configuration.

3. Debugging keyboard-related applications: Developers working on applications that interact with the keyboard can use showkey to understand the key codes their program is receiving.

To exit the showkey command, press Ctrl+C.

Capture Keyboard Input Using the showkey Command

In this step, we will learn how to use the showkey command to capture keyboard input.

First, let's start the showkey command in the terminal:

sudo showkey

This will put the showkey command in a listening mode, waiting for you to press keys on your keyboard.

Now, try pressing some keys on your keyboard. You should see the key codes being displayed in the terminal:

Press any keys - Ctrl-C to end
key pressed 1 is 65 (a)
key pressed 2 is 66 (b)
key pressed 3 is 67 (c)

The output shows the decimal code for each key, as well as the corresponding character in parentheses.

You can also try pressing special keys, such as the arrow keys, function keys, or modifier keys (Shift, Ctrl, Alt). The showkey command will display the corresponding key codes for these as well.

To exit the showkey command, press Ctrl+C.

Analyze the Output of the showkey Command

In this step, we will take a closer look at the output of the showkey command and understand how to interpret the key codes it displays.

Let's start the showkey command again:

sudo showkey

This time, try pressing a few different keys on your keyboard, including letters, numbers, function keys, and special characters. Observe the output:

Press any keys - Ctrl-C to end
key pressed 1 is 97 (a)
key pressed 2 is 98 (b)
key pressed 3 is 99 (c)
key pressed 4 is 49 (1)
key pressed 5 is 50 (2)
key pressed 6 is 51 (3)
key pressed 7 is 9 (Tab)
key pressed 8 is 10 (Enter)
key pressed 9 is 27 (Esc)
key pressed 10 is 32 (Space)
key pressed 11 is 113 (q)
key pressed 12 is 119 (w)
key pressed 13 is 101 (e)

The output shows the decimal code for each key, as well as the corresponding character in parentheses. Here's how to interpret the output:

• The "key pressed" line indicates that a key has been pressed on the keyboard.
• The decimal code represents the scancode or key code for the pressed key. This code is specific to the keyboard hardware and may vary depending on the keyboard layout and manufacturer.
• The character in parentheses represents the ASCII or Unicode character that corresponds to the key code. This is the character that the system will typically interpret and process.

Understanding the showkey output can be useful in the following scenarios:

1. Troubleshooting keyboard issues: If you're experiencing problems with your keyboard, such as certain keys not working or unexpected behavior, the showkey output can help you identify the root cause by showing the key codes being generated.
2. Mapping custom keyboard shortcuts: If you want to create custom keyboard shortcuts or macros, the showkey output can help you determine the key codes to use in your configuration.
3. Debugging keyboard-related applications: Developers working on applications that interact with the keyboard can use showkey to understand the key codes their program is receiving.

To exit the showkey command, press Ctrl+C.

Summary

In this lab, we learned about the purpose and usage of the Linux showkey command. The showkey command allows us to capture and display the key codes generated by the keyboard, which can be useful for troubleshooting keyboard-related issues, mapping custom keyboard shortcuts, and debugging keyboard-related applications. We started the showkey command in the terminal and observed the output, which showed the decimal code for each key pressed, as well as the corresponding character. This information can be valuable for understanding how the keyboard is communicating with the system.

Linux Commands Cheat Sheet