Launching and Closing Apps

So far we've only been opening terminal windows, which is fine if you do most of your work at the command line, but obviously isn't great for general desktop usage. Fortunately, there's a dedicated program launcher for i3 called dmenu that is – as you've probably guessed by now – keyboard-centric. To activate it, press Alt+D and look at the top of the screen: You should see a bar with a gap on the left and various programs listed on the right. (If you don't see this, make sure dmenu is installed – have a search for it in your distro's package manager.)

Now, with dmenu open, start typing something – for example, f. You'll see that dmenu narrows down the list of displayed apps to those beginning with f. Type "fire" and (unless you have other apps installed beginning with fire), it should narrow down to "firefox", so hit Enter to launch it. As you're seeing, dmenu is a useful way to quickly launch applications without having to type in the full executable names – at least, most of the time!

To close an window, press Alt+Shift+Q. This tells i3 to send a regular "close window" command to the application, that is, shutting it down gracefully. So if you're running an editor and haven't saved your work, the app will prompt you. Try it out with, say, LibreOffice – start a word processor document, tap in some text, and then press Alt+Shift+Q. LibreOffice's Save Document? dialog will pop up, and you'll also notice that i3 lets it appear in the middle of the screen, as usual (see the "Using Workspaces" box for more info).

So i3 isn't overly zealous about tiling; it tries to give each window and application its own dedicated space on the screen, making sure no pixels are wasted, but it's also clever enough to respect "floating" windows that are temporary and don't need to be assigned their own tiles. You can see this in Figure 4.

Figure 4: i3 doesn't try to tile absolutely everything, though and respects the wishes of floating dialogs.

You're now ready to start using i3 for your daily work – it may take some time to get used to, but after a while you'll find it much more elegant to work with than regular point-and-click window managers (Figure 5).

Figure 5: A great example of i3 at its best: editing a config file in one tile while viewing its manual page in another.

But one final thing we'll look at is the default configuration file that i3 created when you first launched it. This is called config, and you'll find it in the .config/i3/ subdirectory of your home directory.

Apart from the font option, which lets you customize the font used in window titles and the i3bar, most of the other options are preceded by bindsym and configure the keybindings for the various window management options. For instance, look at this:

bindsym $mod+Shift+q kill

Here, $mod is the modifier key (Alt or Windows) that we selected during the first run of i3 – and it's also defined at the top of the configuration file. So, this line of code says "bind the key combination $mod+Shift+q to the kill command" with kill meaning close the window.

Look through the file to explore the available keybindings – there are a few lesser-used ones that we haven't talked about in this guide, but that you may find useful as time goes on. If there's a particular default keybinding that you find awkward to use, you can simply change it here, save the file, and press Alt+Shift+C to reload the configuration file without having to restart i3 completely. (To exit i3, use Alt+Shift+E and notice the confirmation bar at the top of the screen.)

One last thing: When you're getting to grips with i3, we recommend loading up the i3 Reference Card [3] and making a printout of it for your wall. For the complete i3 documentation, describing many different ways to divide up your screen, see the User's Guide [4]. Also, check out the "Other Tiling WMs" box for alternatives to i3.