How to have dark/light profile selected when opening a new iTerm.

The script

For the script to work you need to have two iTerm profiles, one named Dark and the other one Light. Just go to Preferences then Profiles then Duplicate profile.

I use fish but you can easily adapt that in your .bashrc, .bash_profile etc…

Here is what I have in my ~/.config/fish/config.fish:

function setItermProfile
    echo -ne "\033]50;SetProfile=$argv\a"
end

function sync_appearance

    set -x MacOSThemeAutoSwitch \
        (defaults read -g AppleInterfaceStyleSwitchesAutomatically 2>/dev/null)
    test -z $MacOSThemeAutoSwitch; and set -x MacOSThemeAutoSwitch 0

    set -x MacOSTheme (defaults read -g AppleInterfaceStyle 2>/dev/null)
    test -z $MacOSTheme; and set -x MacOSTheme 'nil'

    if test -n $ITERM_PROFILE # check if we are using iTerm2
        switch $MacOSThemeAutoSwitch
            case 1 # autoswitch on
                switch $MacOSTheme
                    case 'nil'
                        setItermProfile Light
                    case '*'
                        setItermProfile Dark
                end
            case 0 # autoswitch off
                switch $MacOSTheme
                    case 'Dark'
                        setItermProfile Dark
                    case 'Light'
                        setItermProfile Light
                    case 'nil'
                        setItermProfile Light
                end
        end
    end
end

if status --is-login
    if status --is-interactive
        sync_appearance
    end
end

If the appearance change, you can call sync_appearance function in your shell to sync with the OS dark/light appearance.