alacritty-theme-autoswitch-macos

Automatically adjust Alacritty theme according to your current MacOS system theme. (dark/light)

This is a shell script running indefinitely in the background, checking for system theme change every 0.5 seconds using AppleScript. If change is detected, it updates ~/.alacritty.toml with the appropriate theme.

Requirements

• MacOS 14 (Sonoma)
• zsh >= 5.9, set as your shell
• alacritty >= 0.13.2
• Alacritty config must contain live_config_reload = true

The autoswitcher might work on earlier versions of MacOS, but it is not guaranteed.

Install

Before installing the autoswitcher, you need to prepare Alacritty configuration files in your home directory:

• Place all your configuration excluding theming part in ~/.alacritty-base.toml
• Place only the light theme in ~/.alacritty-theme-light.toml
• Place only the dark theme in ~/.alacritty-theme-dark.toml

Install the autoswitcher by running the installation script:

./install.sh

Alternatively, use any method of your choice to ensure .alacritty-theme-autoswitch.sh is launched at login, terminal launch etc.

See examples on how the config files should look like.

The installation script copies .alacritty-theme-autoswitch.sh to your home directory and adds a command to .zshrc to launch it automatically. Launching autoswitcher is idempotent, as it uses file lock to ensure it only runs once at a time.

Start

The autoswitcher is started automatically.

Stop

To stop the script:

pkill -fx "zsh $HOME/.alacritty-theme-autoswitch.sh"

Please note, that as long as .zshrc contains the launch command, autoswitcher will re-launch every time you open a new shell session.

Uninstall

To remove autoswitcher:

• Remove launch command from .zshrc
• Delete the .alacritty-theme-autoswitch.sh from your home directory
• Stop the autoswitcher using the command provided above

FAQ

Can I do this cleaner using AppleScript?

Implementing the same in pure AppleScript is possible and results in similar looping logic. It would have to be compiled as a "stay open application"; making it hidden in the background requires some effort and is arguably less clean. The shell script method is easier.

Why not use import and update the reference?

I dislike inline file editing. The method of joining two source files is robust and easy to understand.