xmodmap (with examples)

Introduction:

The xmodmap command is a utility for modifying keymaps and pointer button mappings in X, the window system used in Unix-like operating systems. By using xmodmap, you can customize the behavior of your keyboard and mouse buttons to suit your preferences and needs. In this article, we will explore several examples that demonstrate the various use cases of the xmodmap command.

Use Case 1: Swapping left-click and right-click on the pointer

Code: xmodmap -e 'pointer = 3 2 1'

Motivation: This use case is useful for users who want to change the default behavior of their mouse buttons. Swapping the left-click and right-click buttons can be particularly helpful for left-handed users or those who prefer a different button configuration.

Explanation: The -e flag specifies an expression to be executed. In this case, the expression 'pointer = 3 2 1' is used to swap the left-click and right-click buttons. The numbers represent the button IDs assigned to each mouse button.

Example Output: After running the command, the left-click and right-click buttons on the pointer will be swapped.

Use Case 2: Reassigning a key on the keyboard to another key

Code: xmodmap -e 'keycode keycode = keyname'

Motivation: This use case is helpful when you want to redefine the functionality of a particular key on your keyboard. For example, you might want to map a less frequently used key to a more commonly used key for convenience.

Explanation: The -e flag is used to specify an expression to be executed. In this case, the expression 'keycode keycode = keyname' is used. Replace keycode with the scancode of the key you want to reassign, keyname with the name of the key you want to use instead, and keyname with the name of the new key.

Example Output: After executing the command, the specified key on the keyboard will be reassigned to the new key.

Use Case 3: Disabling a key on the keyboard

Code: xmodmap -e 'keycode keycode ='

Motivation: There may be situations where you want to disable a particular key on your keyboard. For example, if a key is malfunctioning or if you want to prevent accidental presses of a sensitive key.

Explanation: The -e flag is used to specify an expression to be executed. In this case, the expression 'keycode keycode =' is used to disable the specified key. Replace keycode with the scancode of the key you want to disable.

Example Output: After running the command, the specified key on the keyboard will be disabled, and its functionality will no longer be active.

Use Case 4: Executing all xmodmap expressions in a file

Code: xmodmap path/to/file

Motivation: Sometimes, you may have a collection of xmodmap expressions that you want to execute together. Storing these expressions in a file and using the xmodmap command to execute them all at once can be more convenient than executing each expression individually.

Explanation: The path/to/file argument specifies the path to a file containing xmodmap expressions. The xmodmap command will read the file and execute each expression in sequential order.

Example Output: After running the command, all the xmodmap expressions in the specified file will be executed, resulting in the desired modifications to the keymaps and pointer button mappings.

Conclusion:

The xmodmap command is a powerful utility that allows you to customize the keymaps and pointer button mappings in X. By understanding and utilizing the various use cases of the xmodmap command, you can tailor your keyboard and mouse configurations to suit your preferences. Whether you want to swap mouse buttons, reassign keys, or disable certain keys, xmodmap provides the flexibility to achieve these customizations.