i3-msg (1) Linux Manual Page
i3-msg – send messages to i3 window manager
Synopsis
i3-msg "message"Description
i3-msg is a sample implementation for a client using the unix socket IPC interface to i3. At the moment, it can only be used for sending commands (like in configuration file for key bindings), but this may change in the future (staying backwards-compatible, of course).Example
i3-msg "bp" # Use 1-px border for current client