Mastering `polybar-msg` Commands (with examples)

polybar-msg is a command-line utility that serves as a pivotal tool for enthusiasts of Polybar, a highly customizable status bar often used on Unix-like operating systems. Essentially, polybar-msg empowers users to control and interact with their Polybar setup through inter-process messaging (IPC). While IPC is turned off by default, it can be enabled in the Polybar configuration to unlock a new level of bar manipulation directly from the command line. With polybar-msg, users can effortlessly quit, restart, and toggle their bars, among other powerful actions. Below, we explore each use case with illustrative examples.

Use case 1: Quit the bar

Code:

polybar-msg cmd quit

Motivation: This use case is particularly beneficial when you need to quickly dismiss the Polybar interface. It might be necessary in situations where you want to refresh the desktop environment without a full reboot or to conserve system resources when the bar is not required.

Explanation:

• polybar-msg: The command-line program that interacts with Polybar via IPC.
• cmd: Specifies that the command pertains to controlling the entire bar rather than a specific action or module.
• quit: The specific directive that instructs the bar to terminate execution.

Example Output: Executing the command will not provide any direct output on the screen, as it only results in Polybar shutting down.

Use case 2: Restart the bar in-place

Code:

polybar-msg cmd restart

Motivation: Restarting the bar in-place is essential when changes have been made to the configuration file that need to take effect immediately without having to manually restart the bar. It provides a seamless experience in applying new settings or modules.

Explanation:

• polybar-msg: The communication bridge to Polybar.
• cmd: Indicates a command targeted at overall bar control.
• restart: This tells Polybar to shut down and immediately restart, applying any changes made to configurations or scripts.

Example Output: The command will not visibly output any response but will cause the bar to disappear momentarily and then reappear with applied changes.

Use case 3: Hide the bar

Code:

polybar-msg cmd hide

Motivation: Hiding the bar can be advantageous when you’re seeking an uncluttered desktop environment, especially during presentations or when using full-screen applications that don’t require constant monitoring of Polybar information.

Explanation:

• polybar-msg: Facilitates communication with Polybar.
• cmd: Points to a command affecting the whole bar.
• hide: Directs the bar to become invisible, providing a cleaner screen view.

Example Output: Upon execution, Polybar will not vanish entirely but rather become hidden, ready to be shown again without needing to restart.

Use case 4: Show the bar again

Code:

polybar-msg cmd show

Motivation: This command is useful when you wish to revert to having the bar visible after it has been hidden. This toggling ensures that important system information is readily available as needed.

Explanation:

• polybar-msg: Acts as the IPC interface to Polybar.
• cmd: Specifies a message directing the bar’s behavior.
• show: Reverses the effect of the hide command, making the bar visible again.

Example Output: Executing this command brings the Polybar back into view if it had been previously hidden.

Use case 5: Toggle between hidden/visible

Code:

polybar-msg cmd toggle

Motivation: This toggle functionality provides a swift mechanism to alternate between showing and hiding the bar, offering flexibility and convenience without executing separate show or hide commands.

Explanation:

• polybar-msg: Commands communication with the bar.
• cmd: A command enacted upon the whole bar.
• toggle: Flips the current state of the bar (hidden or visible) to its opposite state.

Example Output: The bar’s visibility status will be reversed efficiently with no direct command-line feedback.

Use case 6: Execute a module action

Code:

polybar-msg action "#module_name.action_name.data_string"

Motivation: Executing module actions directly can become a powerful feature for custom or dynamic Polybar setups where a specific module should perform an action—such as updating its display or triggering external scripts—based on conditions or user input.

Explanation:

• polybar-msg: Manages the interaction with Polybar.
• action: Indicates that the following pertains to a specific module rather than to the bar as a whole.
• #module_name.action_name.data_string: A formatted specification calling a named action on a specific module, optionally using additional data to refine the action performed.

Example Output: Running such a command triggers the associated module action without sending feedback to the terminal; the effect would depend on the module’s functionality.

Use case 7: Only send messages to a specific Polybar instance

Code:

polybar-msg -p pid cmd|action payload

Motivation: When managing multiple Polybar instances, targeting a specific instance allows granular control over which bar receives the command, preventing unintended changes to other bars.

Explanation:

• polybar-msg: Communication with the IPC pathway of Polybar.
• -p pid: Sends the command solely to the Polybar instance identified by a unique process ID (PID).
• cmd|action: Specifies whether the message concerns a global bar command or a particular module action.
• payload: Additional data that details the specific command or action requested.

Example Output: Executing this command influences only the designated bar instance, depending on the provided PID, without terminal output.

Conclusion:

By leveraging polybar-msg, users gain unmatched flexibility and power over their Polybar experience. Each use case illustrated demonstrates its utility—from quitting to specific module actions—proving how IPC facilitates seamless and efficient Polybar management directly from the command line.