How to Use the Command `sm` (Screen Message) (with Examples)

The sm command, originating from the Screen Message utility, is a simple yet powerful tool designed to display text messages in full-screen mode on your computer. This can be quite beneficial if you need to convey messages in a visually striking manner on projection screens, during presentations, or even as a fun way to send a message across to someone using a shared screen. The command supports various customization options to rotate the message, change colors, and even take input from other command outputs. Its ease of use is enhanced by its compatibility with Linux systems and its open-source nature.

Use Case 1: Display a Message in Full-Screen

Code:

sm "Hello World!"

Motivation:

Sometimes, the simplest messages are the most effective. Displaying a full-screen message can be a straightforward yet powerful way to catch attention. For instance, during a presentation or lecture when you need everyone to focus on a single, important point, quickly flashing it full-screen can focus attention immediately. Additionally, in collaborative workspaces, such a tool ensures everyone sees critical information simultaneously.

Explanation:

• sm: Invokes the screen message command, initiating the action to display a message.
• "Hello World!": The text you want to appear full-screen. This is the content of your message - in this case, the classic “Hello World!” phrase used widely in programming beginners’ examples.

Example Output:

When executed, the screen will switch from whatever current display is there to a full-size view prominently showing “Hello World!” across the screen, rendering any background activity invisible until the message exits or is closed.

Use Case 2: Display a Message with Inverted Colors

Code:

sm -i "Hello World!"

Motivation:

Inverting colors can significantly increase readability in certain lighting conditions or when displayed on different screens and projectors that may not handle color consistently. It’s especially beneficial for people with visual impairments as it can enhance contrast, making it easier to read the text.

Explanation:

• sm: Initiates the screen message utility.
• -i: Stands for “invert colors,” flipping the usual foreground and background color relationship to present the message in inverted colors.
• "Hello World!": The message content to display.

Example Output:

On running this command, the system displays the full-screen message “Hello World!” with colors inverted from their typical setup, making the text stand out against the altered background.

Use Case 3: Display a Message with Custom Foreground Color

Code:

sm -f blue "Hello World!"

Motivation:

Customizing text color can help with brand identity presentation, emphasize parts of a text, or simply make messages aesthetically pleasing. For environments like classrooms or branding events, using colors to differentiate messages or to match a specific theme can enhance the viewer’s experience and retention.

Explanation:

• sm: Calls the screen message tool.
• -f blue: The -f option specifies a custom foreground (text) color. In this example, the text will appear in blue.
• "Hello World!": The message to be displayed on screen.

Example Output:

The screen message “Hello World!” will appear full-screen in a calm blue color, replacing the default white foreground.

Use Case 4: Display a Message with Custom Background Color

Code:

sm -b #008888 "Hello World!"

Motivation:

Adjusting the background color might be necessary for various aesthetic or functional reasons. This adjustment can cater to improved contrast for better readability, matching organizational color schemes, or reducing monitor glare in specific environments.

Explanation:

• sm: Triggers the screen message display function.
• -b #008888: Uses a hexadecimal color code to define a custom background color. ‘#008888’ provides a teal-like hue for the background.
• "Hello World!": This is the message content.

Example Output:

Execution will result in a full-screen message showing “Hello World!” with a teal-like background, standing out sharply due to its non-standard color contrast compared to the default.

Use Case 5: Display a Message Rotated 3 Times (in Steps of 90 Degrees, Counterclockwise)

Code:

sm -r 3 "Hello World!"

Motivation:

Rotating messages can be a creative way to catch viewers’ attention, especially at interactive exhibits or digital kiosks. It can also be practical for accommodating viewing needs in unusual display configurations or when using an array of connected screens.

Explanation:

• sm: Starts the screen message display.
• -r 3: This rotates the text three times, each by 90 degrees in a counterclockwise direction, effectively making the text upside-down on the final display.
• "Hello World!": The content intended for full-screen display.

Example Output:

The “Hello World!” message appears inverted but still occupies the entire screen, adding a creative twist to the otherwise straightforward text display.

Use Case 6: Display a Message Using the Output from Another Command

Code:

echo "Hello World!" | sm -

Motivation:

Piping input from other commands enables dynamic message display based on real-time data, outputs, or pre-programmed scripts. This flexibility is useful for showing time-sensitive information like system status messages, quotes, or live-updated statistics.

Explanation:

• The first part, echo "Hello World!", generates the message to be displayed.
• The | symbol pipes the output from the echo command directly into the sm command.
• sm -: Accepts message content from the standard input (stdin) to display.

Example Output:

“Hello World!” is displayed full-screen as a result after the echo command processes the text and hands it to sm.

Conclusion

The sm utility showcases its versatility through these diverse use cases. Whether for simplifying presentation displays, catering to color preferences and accessibility, creatively presenting texts, or dynamically loading messages via system commands, sm proves to be a handy command-line tool for anyone needing an uncomplicated, fullscreen text display solution on Linux systems.