dotfiles/.config/i3/README.org

i3 Window Manager Configuration

• i3 Configuration
  • Header
  • Basic Settings
  • System Management
  • Audio Controls
  • Brightness Controls
  • Window Appearance
  • Window Management
  • Navigation
  • Layout Management
  • Workspaces
  • System Commands
  • Status Bar
  • Program Shortcuts
  • Focus Behavior
  • Workspace Assignments
  • Autostart Applications
  • Scripts
  • Appearance
• Setting Up Auto-Tangle

i3 Configuration

This is my personal configuration for the i3 window manager. It's written using Org Mode's literate programming features, which allows embedding documentation directly alongside the code. This file is configured to automatically "tangle" the code blocks into the actual i3 configuration file (named config in the same directory) whenever this Org file is saved in Emacs (see the Setting Up Auto-Tangle section). This approach keeps the configuration well-documented and easier to manage.

Header

This is just a simple header block containing ASCII art with personal information, which will appear at the top of the tangled config file.

#
# ██████╗  ██████╗  ██████╗ ███████╗
# ██╔══██╗██╔═══██╗██╔════╝ ██╔════╝     Roger Gonzalez
# ██████╔╝██║   ██║██║  ███╗███████╗     https://rogs.me
# ██╔══██╗██║   ██║██║   ██║╚════██║
# ██║  ██║╚██████╔╝╚██████╔╝███████║
# ╚═╝  ╚═╝ ╚═════╝  ╚═════╝ ╚══════╝

Basic Settings

Here, we define some fundamental settings for i3.

• $mod: Sets the primary modifier key. Mod4 is typically the Super key (Windows key).
• $aux: Sets an auxiliary modifier key. Mod1 is usually the Alt key. Using an auxiliary modifier allows for more keybinding combinations without conflicts.
• font: Specifies the font used for window titles and, by default, the i3bar. pango:DejaVu Sans Mono enables Pango for text rendering, which provides better support for Unicode glyphs (like icons), right-to-left text, and improved scaling on high-resolution displays.

set $mod Mod4
set $aux Mod1

font pango:DejaVu Sans Mono

System Management

This section configures integration with system services and utilities.

• xss-lock: Automatically locks the screen using a specified script (~/.config/i3/scripts/i3lock_script.sh) before the system suspends. It uses `logind` to manage sleep inhibitors. You can manually lock the screen using loginctl lock-session.
• nm-applet: Starts the NetworkManager applet, providing a system tray icon for managing network connections (especially useful for Wi-Fi).
• autorandr: Manages display configurations. exec_always ensures it runs on startup and i3 restart. The sleep 2 might be necessary to wait for monitors to be fully detected. A keybinding ($mod+Shift+x) is also set to manually trigger a display profile change.

exec --no-startup-id xss-lock --transfer-sleep-lock ~/.config/i3/scripts/i3lock_script.sh

exec --no-startup-id nm-applet

# Screen resolution
exec_always --no-startup-id sleep 2; autorandr --change
bindsym $mod+Shift+x exec autorandr --change

Audio Controls

Keybindings for controlling audio volume and media playback.

• Volume control uses pactl (PulseAudio Control) to adjust the volume and mute status of the default audio sink (output) and source (input/microphone).
• $refresh_i3status: This variable defines a command to send the SIGUSR1 signal to the i3status process. This is commonly used to tell status bars (like i3bar or Polybar when using the i3status module) to refresh their display immediately after a change (like volume).
• Media keys (Next, Previous, Play/Pause) are bound to playerctl, a command-line utility to control MPRIS-compatible media players (like Spotify, VLC, etc.).

set $refresh_i3status killall -SIGUSR1 i3status
bindsym XF86AudioRaiseVolume exec --no-startup-id pactl set-sink-volume @DEFAULT_SINK@ +10% && $refresh_i3status
bindsym XF86AudioLowerVolume exec --no-startup-id pactl set-sink-volume @DEFAULT_SINK@ -10% && $refresh_i3status
bindsym XF86AudioMute exec --no-startup-id pactl set-sink-mute @DEFAULT_SINK@ toggle && $refresh_i3status
bindsym XF86AudioMicMute exec --no-startup-id pactl set-source-mute @DEFAULT_SOURCE@ toggle && $refresh_i3status

bindsym XF86AudioNext exec playerctl next
bindsym XF86AudioPrev exec playerctl previous
bindsym XF86AudioPlay exec playerctl play-pause

Brightness Controls

Bindings for adjusting screen brightness using the dedicated function keys found on many laptops. It uses the xbacklight utility.

bindsym XF86MonBrightnessUp exec xbacklight -inc 20
bindsym XF86MonBrightnessDown exec xbacklight -dec 20

Window Appearance

Settings related to how windows look and are arranged.

• for_window [class".*"] border pixel 2=: This rule applies to all windows (matched by the regex .*) and sets their border style to pixel with a thickness of 2 pixels. This effectively hides the default title bars, saving screen space.
• gaps inner 4 / gaps outer 4: Configures gaps (empty space) between windows (inner) and between windows and screen edges (outer).
• The smart_gaps on line (commented out) would automatically remove outer gaps if there's only one window on the workspace.
• Keybindings are provided to dynamically adjust or reset inner and outer gaps during the session.

# Disable titlebars
for_window [class=".*"] border pixel 2

# Use gaps
# smart_gaps on
gaps inner 4
gaps outer 4

bindsym $mod+Shift+t gaps inner current set 4; gaps outer current set 4
bindsym $mod+s gaps inner current plus 5
bindsym $mod+Shift+s gaps inner current minus 5
bindsym $mod+Shift+d gaps inner current set 0; gaps outer current set 0
bindsym $mod+z gaps outer current plus 5
bindsym $mod+Shift+z gaps outer current minus 5

Window Management

Core bindings for managing windows.

• floating_modifier $mod: Allows dragging floating windows by holding the $mod key (Super) and clicking/dragging with the mouse.
• $terminal / $auxTerminal: Defines variables for the preferred terminal emulator (alacritty) and an auxiliary one (ghostty).
• $mod+Return: Opens a new instance of the default terminal ($terminal).
• $mod+Shift+q: Kills the currently focused window.
• $mod+d: Launches rofi in combi mode, allowing searching for and launching applications (drun) or switching to open windows (window).

# Use Mouse+$mod to drag floating windows to their wanted position
floating_modifier $mod

# start a terminal
set $terminal alacritty
set $auxTerminal ghostty
bindsym $mod+Return exec $terminal

# kill focused window
bindsym $mod+Shift+q kill

# start rofi (a program launcher)
bindsym $mod+d exec --no-startup-id "rofi -combi-modi window,drun -show combi"

Navigation

Keybindings for changing focus between windows and moving windows around.

• Focus changes can be done using Vim-style keys (h, j, k, l) or the standard arrow keys, combined with the $mod key.
• Moving windows uses the same keys but adds the Shift modifier (e.g., $mod+Shift+h moves the focused window left).
• A dedicated "Resize" mode is defined, activated by $mod+r. While in this mode, the h, j, k, l keys resize the focused window. Pressing Return or Escape exits the resize mode and returns to the default keybinding set.

# change focus
bindsym $mod+h focus left
bindsym $mod+j focus down
bindsym $mod+k focus up
bindsym $mod+l focus right

# alternatively, you can use the cursor keys:
bindsym $mod+Left focus left
bindsym $mod+Down focus down
bindsym $mod+Up focus up
bindsym $mod+Right focus right

# move windows:
bindsym $mod+Shift+h move left
bindsym $mod+Shift+j move down
bindsym $mod+Shift+k move up
bindsym $mod+Shift+l move right

# alternatively, you can use the cursor keys:
bindsym $mod+Shift+Left move left
bindsym $mod+Shift+Down move down
bindsym $mod+Shift+Up move up
bindsym $mod+Shift+Right move right

bindsym $mod+r mode "Resize"

mode "Resize" {
    bindsym h resize shrink width 10 px or 10 ppt
    bindsym j resize grow height 10 px or 10 ppt
    bindsym k resize shrink height 10 px or 10 ppt
    bindsym l resize grow width 10 px or 10 ppt

    bindsym Return mode "default"
    bindsym Escape mode "default"
}

Layout Management

Bindings for controlling the layout of window containers.

• $mod+t: Toggles the split orientation (horizontal/vertical) for the current container. New windows will be placed accordingly.
• $mod+f: Toggles fullscreen mode for the focused window or container.
• $mod+w / $mod+e: Change the layout mode of the current container. tabbed shows windows like tabs in a browser. toggle split switches between the default split layout and stacked layout (titles shown vertically).
• $mod+Shift+space: Toggles the focused window between tiling (managed by i3's layout) and floating (can be moved/resized freely).
• $mod+space: Switches focus between tiling and floating windows on the current workspace.
• $mod+a: Moves focus to the parent container, useful for applying layout changes or moving multiple windows together.

# toggle split orientation
bindsym $mod+t split toggle

# enter fullscreen mode for the focused container
bindsym $mod+f fullscreen toggle

# change container layout (stacked, tabbed, toggle split)
bindsym $mod+w layout tabbed
bindsym $mod+e layout toggle split

# toggle tiling / floating
bindsym $mod+Shift+space floating toggle

# change focus between tiling / floating windows
bindsym $mod+space focus mode_toggle

# focus the parent container
bindsym $mod+a focus parent

Workspaces

Configuration related to i3 workspaces (virtual desktops).

• Workspace names are defined using variables ($ws1, $ws2, etc.). This makes it easy to change names later. Icons (like , ) are used, requiring a Nerd Font or similar for proper display in the status bar.
• Keybindings $mod+[1-0] switch to the corresponding workspace. $mod+$aux+0 switches to workspace 11.
• Keybindings $mod+Shift+[1-0] move the focused container to the corresponding workspace. $mod+$aux+Shift+0 moves to workspace 11.
• Workspaces are explicitly assigned to specific monitor outputs (`primary`, `DP-2-1`, `DP-2-2`). This ensures a consistent workspace layout across multiple monitors. Odd-numbered workspaces appear on the primary monitor, even-numbered on the second, and workspace 11 on the third.

# Define names for default workspaces for which we configure key bindings later on.
# We use variables to avoid repeating the names in multiple places.
set $ws1 "1: "
set $ws2 "2: "
set $ws3 "3: "
set $ws4 "4: "
set $ws5 "5: "
set $ws6 "6: "
set $ws7 "7: "
set $ws8 "8"
set $ws9 "9"
set $ws10 "10"
set $ws11 "11: "

# switch to workspace
bindsym $mod+1 workspace number $ws1
bindsym $mod+2 workspace number $ws2
bindsym $mod+3 workspace number $ws3
bindsym $mod+4 workspace number $ws4
bindsym $mod+5 workspace number $ws5
bindsym $mod+6 workspace number $ws6
bindsym $mod+7 workspace number $ws7
bindsym $mod+8 workspace number $ws8
bindsym $mod+9 workspace number $ws9
bindsym $mod+0 workspace number $ws10
bindsym $mod+$aux+0 workspace number $ws11

# move focused container to workspace
bindsym $mod+Shift+1 move container to workspace number $ws1
bindsym $mod+Shift+2 move container to workspace number $ws2
bindsym $mod+Shift+3 move container to workspace number $ws3
bindsym $mod+Shift+4 move container to workspace number $ws4
bindsym $mod+Shift+5 move container to workspace number $ws5
bindsym $mod+Shift+6 move container to workspace number $ws6
bindsym $mod+Shift+7 move container to workspace number $ws7
bindsym $mod+Shift+8 move container to workspace number $ws8
bindsym $mod+Shift+9 move container to workspace number $ws9
bindsym $mod+Shift+0 move container to workspace number $ws10
bindsym $mod+$aux+Shift+0 move container to workspace number $ws11

workspace $ws1 output primary
workspace $ws3 output primary
workspace $ws5 output primary
workspace $ws7 output primary
workspace $ws9 output primary

workspace $ws2 output DP-2-1
workspace $ws4 output DP-2-1
workspace $ws6 output DP-2-1
workspace $ws8 output DP-2-1
workspace $ws10 output DP-2-1

workspace $ws11 output DP-2-2

System Commands

Bindings for managing the i3 session and the system itself.

• $mod+Shift+c: Reloads the i3 configuration file (~/.config/i3/config). Useful after making changes.
• $mod+Shift+r: Restarts i3 in place. This preserves the current layout and session, useful for applying changes that require a restart or upgrading i3.
• $Locker: Defines a variable for the screen locking command, using the same script as xss-lock.
• A "System" mode (similar to the "Resize" mode) is defined for power management actions. Activated by $mod+Shift+e, it provides single-key shortcuts for locking (l), logging out (e), suspending (s), hibernating (h), rebooting (r), and shutting down (Shift+s). Pressing Return or Escape exits this mode.

# reload the configuration file
bindsym $mod+Shift+c reload
# restart i3 inplace (preserves your layout/session, can be used to upgrade i3)
bindsym $mod+Shift+r restart
# lock the screen
set $Locker exec "~/.config/i3/scripts/i3lock_script.sh"

set $mode_power System (l) lock, (e) logout, (s) suspend, (h) hibernate, (r) reboot, (Shift+s) shutdown
mode "$mode_power" {
    bindsym l exec --no-startup-id $Locker, mode "default"
    bindsym e exec --no-startup-id i3-msg exit, mode "default"
    bindsym s exec --no-startup-id systemctl suspend, mode "default"
    bindsym h exec --no-startup-id systemctl hibernate, mode "default"
    bindsym r exec --no-startup-id systemctl reboot, mode "default"
    bindsym Shift+s exec --no-startup-id systemctl poweroff -i, mode "default"

    # back to normal: Enter or Escape
    bindsym Return mode "default"
    bindsym Escape mode "default"
}

bindsym $mod+Shift+e mode "$mode_power"

Status Bar

This section handles the status bar. Instead of using the default i3bar with i3status, this configuration uses Polybar.

• exec_always --no-startup-id .config/polybar/launch.sh: Executes a script located at .config/polybar/launch.sh on i3 startup and restart. This script is responsible for launching and configuring the Polybar instances. The actual appearance and content of the bar are defined in the Polybar configuration files, not here.

# Start Polybar
exec_always --no-startup-id .config/polybar/launch.sh

Program Shortcuts

Custom keybindings to launch frequently used applications and perform specific actions.

• $aux+f: Opens Thunar file manager.
• $aux+c: Opens an image viewer (`xviewer`) showing a Vim cheatsheet.
• $aux+a: Opens `lxappearance` for changing GTK themes, icons, and fonts.
• $mod+Shift+b: Opens the auxiliary terminal ($auxTerminal, ghostty) running a script named `bmenu`.
• Language Switching: $aux+Shift+e sets the keyboard layout to Spanish (es), $aux+Shift+u sets it to US English (us) using setxkbmap.
• Screenshots: Various bindings using scrot and flameshot for capturing the full screen, a selected area (saving to file or clipboard), or launching the Flameshot GUI. The --release flag triggers the action when the key is released.
• Do Not Disturb: $mod+m toggles a Do Not Disturb mode via a custom script.
• Custom Shortcuts: Bindings using $aux to open specific LibreOffice Calc spreadsheets (loffice) and the Feishin music player.

# Hotkeys for opening programs
bindsym $aux+f exec /usr/bin/thunar
bindsym $aux+c exec xviewer ~/.vim-cheatsheet.gif
bindsym $aux+a exec /usr/bin/lxappearance
bindsym $mod+Shift+b exec $auxTerminal -e 'bmenu'

# Languages
bindsym $aux+Shift+e exec setxkbmap es
bindsym $aux+Shift+u exec setxkbmap us

# Screenshots
bindsym Print exec scrot ~/Pictures/%Y-%m-%d-%H%M%S.png
bindsym --release Shift+F12 exec scrot -s -f ~/Pictures/%Y-%m-%d-%H%M%S.png
bindsym --release Ctrl+Shift+F12 exec scrot -s -f -o "/tmp/image.png" && xclip -selection clipboard -t image/png -i /tmp/image.png
bindsym --release Ctrl+Shift+F11 exec flameshot gui

# Do not disturb
bindsym $mod+m exec "~/.config/i3/scripts/toggle_dnd.sh"

# Shortcuts

bindsym $aux+g exec loffice ~/Documents/Gastos/Gastos\ USD.ods
bindsym $aux+b exec loffice ~/Documents/Gastos/BTC.ods
bindsym $aux+l exec feishin

Focus Behavior

Configures how window focus changes in relation to the mouse cursor.

• focus_follows_mouse no: Disables focus follows mouse. This means a window only gains focus when explicitly clicked on, not just when the mouse cursor moves over it. This can prevent accidental focus changes.

# Disable focus follows
focus_follows_mouse no

Workspace Assignments

Rules to automatically assign specific applications to predefined workspaces when they are opened. This helps maintain an organized workflow. Assignments are based on the window class (obtained using tools like `xprop`).

• Browsers (LibreWolf, Firefox, etc.) go to $ws1 (Workspace 1). Brave goes to $ws10.
• Development tools (Emacs, Postman, DBeaver) go to $ws2. Note the use of `for_window … move` for DBeaver, which might be necessary if `assign` doesn't work reliably for that specific application.
• Terminals (Alacritty, ghostty) go to $ws3.
• Communication apps (Slack, Telegram, Signal, etc.) go to $ws4.
• Mail/Calendar apps (Evolution, Thunderbird, Mailspring) go to $ws5.
• Music players (Spotify, Lollypop, Feishin, etc.) go to $ws6.
• File managers (Thunar, Pcmanfm) go to $ws7.
• Miscellaneous utilities (KeePassXC, Bitwarden, Joplin, KDE Connect, Liferea, NewsFlash) are assigned to $ws8 and $ws9.
• Floating Rules: Specific windows (like file transfer dialogs, Galculator, GParted, Nitrogen) are set to open in floating mode automatically.
• Urgent Focus: for_window [urgent=latest] focus automatically switches focus to a workspace containing a window that has set its "urgent" hint (e.g., a new chat message notification).

# Workspace Assignments
# 1: Browsers
assign [class="Brave"] $ws10
assign [class="LibreWolf"] $ws1
assign [class="firefox"] $ws1
assign [class="zen"] $ws1
assign [class="qutebrowser"] $ws1

# 2: Development
assign [class="Emacs"] $ws2
assign [class="Postman"] $ws2
for_window [class="DBeaver"] move to workspace $ws2

# 3: Terminal
assign [class="Alacritty"] $ws3
assign [class="ghostty"] $ws3

# 4: Communication
assign [class="Slack"] $ws4
assign [class="Telegram"] $ws4
assign [class="Keybase"] $ws4
assign [class="Ferdi"] $ws4
assign [class="Signal"] $ws4
assign [class="Element"] $ws4

# 5: Mail/Calendar
assign [class="Evolution"] $ws5
assign [class="thunderbird"] $ws5
assign [class="Mailspring"] $ws5

# 6: Music
for_window [class = "Spotify"] move to workspace $ws6
assign [class="Lollypop"] $ws6
assign [class="feishin"] $ws6
assign [class="Clementine"] $ws6
assign [class="Sublime-music"] $ws6

# 7: File managers
assign [class="Thunar"] $ws7
assign [class="Pcmanfm"] $ws7

# 8: Misc
assign [class="KeePassXC"] $ws8
assign [class="Bitwarden"] $ws8
assign [class="Joplin"] $ws9
assign [class="kdeconnect.app"] $ws9
assign [class="Liferea"] $ws9
assign [class="NewsFlash"] $ws9


# Open specific applications in floating mode
for_window [title="File Transfer*"] floating enable
for_window [class="(Galculator|GParted|Nitrogen|Wireguard)"] floating enable border normal

# switch to workspace with urgent window automatically
for_window [urgent=latest] focus

Autostart Applications

Applications and services launched automatically when i3 starts. The --no-startup-id flag prevents i3 from showing a "busy" cursor while these applications load. sleep commands are used to stagger the startup of some applications, potentially reducing initial resource load or waiting for dependencies (like network or system tray) to become ready.

• Core applications like Thunderbird (mail), Emacs (editor), Zen Browser, and a terminal instance are started with delays.
• nitrogen --restore: Restores the previously set wallpaper.
• blueman-applet: System tray applet for Bluetooth management.
• polkit-gnome-authentication-agent-1: Handles PolicyKit authentication requests (e.g., for administrative tasks).
• gnome-keyring-daemon: Manages passwords and secrets.
• unclutter: Hides the mouse cursor when idle.
• xfce4-power-manager: Handles power management events (like laptop lid close, battery levels).
• pamac-tray: Provides notifications for package updates (on Arch-based systems using Pamac).
• picom: A compositor, responsible for visual effects like transparency, shadows, and fading. exec_always ensures it restarts if it crashes.
• xfce4-notifyd: A notification daemon to display desktop notifications.
• autotiling: A script that automatically adjusts the split direction (horizontal/vertical) based on window dimensions, aiming for a more balanced layout.
• xinput set-prop 14 345 1: Likely a specific command to configure a touchpad or mouse setting (device ID 14, property 345 set to 1). This is hardware-specific.
• play-with-mpv: Likely related to a browser extension that allows opening videos in the MPV player.
• ~/.config/i3/connect-speakers.sh: A custom script, probably for setting up audio outputs.
• kdeconnect-app: Starts the KDE Connect application for integrating phone notifications and file sharing.
• dbus-update-activation-environment: Ensures important environment variables (like DISPLAY) are available to D-Bus activated services, which is crucial for proper integration of many modern desktop applications.

# Autostarts
exec --no-startup-id sleep 20; exec /usr/bin/thunderbird
exec --no-startup-id sleep 10; exec emacsclient -c -a emacs
exec --no-startup-id sleep 20; exec /usr/bin/zen-browser
exec --no-startup-id sleep 5; exec $terminal
exec --no-startup-id sleep 10; exec nitrogen --restore
exec --no-startup-id blueman-applet
exec --no-startup-id /usr/lib/polkit-gnome/polkit-gnome-authentication-agent-1
exec --no-startup-id /usr/bin/gnome-keyring-daemon --start --components=pkcs11,secrets,ssh
exec --no-startup-id /usr/bin/unclutter
exec --no-startup-id xfce4-power-manager
exec --no-startup-id pamac-tray
exec_always --no-startup-id sleep 5; exec picom
exec --no-startup-id /usr/lib/xfce4/notifyd/xfce4-notifyd
exec_always --no-startup-id autotiling
exec --no-startup-id xinput set-prop 14 345 1
exec --no-startup-id exec /usr/bin/play-with-mpv
exec --no-startup-id exec "~/.config/i3/connect-speakers.sh"
exec --no-startup-id sleep 5; exec /usr/bin/kdeconnect-app
exec dbus-update-activation-environment --systemd DBUS_SESSION_BUS_ADDRESS DISPLAY XAUTHORITY &

Scripts

Execution of custom scripts and miscellaneous bindings.

• internet_check.sh (commented out) and weather_notify.sh are custom scripts launched at startup (likely for status bar information or notifications).
• $aux+p: A keybinding that generates a 50-character random password using /dev/urandom and tr, copies it to the clipboard using xclip, and sends a notification.

# Small scripts
# exec --no-startup-id ~/.config/i3/scripts/internet_check.sh &
exec --no-startup-id ~/.config/i3/scripts/weather_notify.sh &

# Random scripts
## Generate a random password and copy it to the clipboard
bindsym $aux+p exec --no-startup-id "tr -dc 'A-Za-z0-9!#$%&'\''()*+,-./:;<=>?@[\]^_`{|}~' </dev/urandom | head -c 50 | xclip -selection clipboard && notify-send 'Copied a random password to the clipboard' -i password"

Appearance

Defines the colors used for window borders and title bars (though title bars are effectively hidden by the `border pixel` setting earlier, these colors still define the border appearance). Colors are specified for different window states: focused, inactive focused, unfocused, urgent, and placeholder. Each line defines colors for the border, background, text, indicator (used in tabbed/stacked layouts), and child border.

# Window colors
# class                 border  backgr. text    indicator child_border
client.focused          #75D85A #75D85A #424242 #75D85A   #75D85A
client.focused_inactive #3B4B58 #3B4B58 #ffffff #3B4B58   #3B4B58
client.unfocused        #202932 #202932 #7A7A7A #202932   #202932
client.urgent           #990000 #990000 #ffffff #990000   #990000
client.placeholder      #0c0c0c #0c0c0c #ffffff #000000   #0c0c0c

Setting Up Auto-Tangle

This final section provides instructions for users of Emacs on how to enable the automatic tangling feature used by this configuration file. It involves adding a small piece of Emacs Lisp code to the user's Emacs configuration (~/.emacs.d/init.el or similar). This code defines a function org-babel-auto-tangle that checks if an Org file being saved has the #+auto_tangle: t property set. If it does, it automatically runs org-babel-tangle, extracting the code blocks into the target file specified by the :tangle header argument (in this case, the config file). This function is then added to the after-save-hook, ensuring it runs every time an Org file is saved.

;; Auto-tangle configuration files
(use-package org
  :config
  (defun org-babel-auto-tangle ()
    "Automatically tangle org files when saved."
    (when (eq major-mode 'org-mode)
      (let ((auto-tangle (cdr (assoc "auto_tangle" (org-collect-keywords '("PROPERTY"))))))
        (when (and auto-tangle (string= auto-tangle "t"))
          (org-babel-tangle)))))
  (add-hook 'after-save-hook #'org-babel-auto-tangle))