How to Use the Command 'dmenu' (with Examples)

The ‘dmenu’ command is a dynamic menu tool that allows users to create interactive menus from text input. It can be invaluable for those looking for a way to streamline item selection processes in their workflows. By reading a list of items from standard input (with each item on a new line), ‘dmenu’ offers a simple interface for users to choose an item from the list. This can be particularly useful in various scripting and automation tasks, as well as in daily computing tasks where quick selection from a large list of options is valuable. To understand its versatility, let’s explore various use cases of the ‘dmenu’ command with detailed explanations and examples.

Use Case 1: Display a Menu of the Output of the ls Command

Code:

ls | dmenu

Motivation:

Displaying a menu of the files and directories available in the current working directory helps users quickly select a file for further actions such as editing, opening, or processing. By using dmenu, file navigation becomes faster and more intuitive, especially when dealing with a large number of files.

Explanation:

• ls: Lists all files and directories in the current directory.
• |: Pipes the output of the ls command as input to dmenu.
• dmenu: Displays the output from ls as a selectable menu.

Example Output:

After executing the command, a menu will appear with a list of files and directories, from which the user can make a selection.

Use Case 2: Display a Menu with Custom Items Separated by a New Line

Code:

echo -e "red\ngreen\nblue" | dmenu

Motivation:

Creating a custom menu with predefined options like colors, items, or actions can save time and reduce the risk of input errors. For example, a programmer could use this to select configurable parameters for a script more efficiently.

Explanation:

• echo -e: Used to enable interpretation of backslash escapes.
• "red\ngreen\nblue": A string with newline-separated items, which represents different options.
• |: Pipes the custom string into dmenu.

Example Output:

A dynamic menu will display “red”, “green”, and “blue”, allowing the user to select one.

Use Case 3: Let the User Choose Between Multiple Items and Save the Selected One to a File

Code:

echo -e "red\ngreen\nblue" | dmenu > color.txt

Motivation:

Saving user selections into a file is important for logging, auditing, or further processing with scripts. For instance, a script could later read color.txt to apply the user’s choice to change interface themes or settings.

Explanation:

• echo -e: Constructs the list of colors.
• dmenu: Interactively displays the list.
• >: Redirects the selected output into color.txt.

Example Output:

If the user selects “green”, color.txt will contain the line “green”.

Use Case 4: Launch dmenu on a Specific Monitor

Code:

ls | dmenu -m 1

Motivation:

In multi-monitor setups, specifying which screen the menu should appear on can enhance usability and efficiency, making sure the menu appears where the user is currently focusing.

Explanation:

• dmenu -m 1: The -m flag specifies the monitor on which dmenu should appear. In this case, it will appear on monitor 1.

Example Output:

The dmenu interface will be displayed on the specified monitor with the files and directories listed.

Use Case 5: Display dmenu at the Bottom of the Screen

Code:

ls | dmenu -b

Motivation:

For users who prefer taskbars and other menus to appear at the bottom of the screen, this option provides a consistent and user-friendly interface placement.

Explanation:

• dmenu -b: The -b flag instructs dmenu to appear at the bottom of the screen instead of the top.

Example Output:

The dmenu will be shown at the bottom of the screen with the list of current directory files and directories as the options.

Conclusion:

‘dmenu’ is a versatile command-line tool capable of enhancing user interaction in a variety of scenarios, from simple file selection to complex script-driven configurations. Each use case demonstrates its ability to dynamically present and manage choices, accommodating user preferences whether they’re working on single or multi-screen setups or require specific menu positioning. The examples provided illustrate how ‘dmenu’ can integrate smoothly into everyday computing tasks, enhancing productivity and workflow efficiency.