polybar, polybar-msg: add page (#10446)

pages/common/polybar-msg.md

@@ -0,0 +1,33 @@
+# polybar-msg
+
+> Control `polybar` using inter-process-messaging (IPC).
+> Note: IPC is disabled by default and can be enabled by setting `enable-ipc = true` in the Polybar config.
+> More information: <https://polybar.rtfd.io/en/stable/user/ipc.html>.
+
+- Quit the bar:
+
+`polybar-msg cmd quit`
+
+- Restart the bar in-place:
+
+`polybar-msg cmd restart`
+
+- Hide the bar (does nothing if the bar is already hidden):
+
+`polybar-msg cmd hide`
+
+- Show the bar again (does nothing if the bar is not hidden):
+
+`polybar-msg cmd show`
+
+- Toggle between hidden/visible:
+
+`polybar-msg cmd toggle`
+
+- Execute a module action (the data string is optional):
+
+`polybar-msg action "#{{module_name}}.{{action_name}}.{{data_string}}"`
+
+- Only send messages to a specific Polybar instance (all instances by default):
+
+`polybar-msg -p {{pid}} {{cmd|action}} {{payload}}`