i3bar

i3bar is the status bar component of the i3 window manager. It provides a horizontal bar for displaying information and controls, typically placed at the top of the screen but configurable to other positions. i3bar itself is driven by a status command that outputs a stream of blocks in a JSON format, which i3bar renders.

Operation: i3bar does not generate the information it displays. Instead, it consumes a JSON stream from a status command, such as i3status, i3blocks, or a custom script. Each block in the stream describes a piece of information with fields like full_text, short_text, color, background, border, min_width, align, and name.

Configuration: The i3 configuration file specifies bar settings, including status_command, position, font, color scheme, and whether system trays are shown. The status command can be any program that outputs valid JSON blocks; common choices are i3status or i3blocks, though many users write tailored scripts.

Interactivity and layout: Blocks can influence the bar’s appearance and behavior through their fields. New blocks are added or removed by the status_command, and blocks can indicate urgency or alignment. Click actions, if supported by the status command, allow simple interactions such as launching a script when a block is clicked.

Relation and ecosystem: i3bar is the standard bar for the i3 window manager, compatible with other bar technologies and scripting approaches. It coexists with alternatives like polybar, which offer more features but also add complexity.