Switch iTerm2 color preset automatic base on macOS dark mode.

iterm2_switch_automatic.md

The latest beta (3.5) includes separate color settings for light & dark mode. Toggling dark mode automatically switches colors.

Vist iTerm2 homepage or use brew install iterm2-beta to download the beta. Thanks @stefanwascoding.

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1. Add switch_automatic.py to ~/Library/Application Support/iTerm2/Scripts/AutoLaunch with:

#!/usr/bin/env python3

import asyncio
import iterm2
import os

light_theme = "GitHub Light Default" # "Light Background"
dark_theme = "GitHub Dark Default" # "Dark Background"

async def changeTheme(theme_parts, connection):
    # Themes have space-delimited attributes, one of which will be light or dark.
    if "dark" in theme_parts:
        preset = await iterm2.ColorPreset.async_get(connection, dark_theme)
    else:
        preset = await iterm2.ColorPreset.async_get(connection, light_theme)

    # Update the list of all profiles and iterate over them.
    profiles=await iterm2.PartialProfile.async_query(connection)
    for partial in profiles:
        # Fetch the full profile and then set the color preset in it.
        profile = await partial.async_get_full_profile()
        await profile.async_set_color_preset(preset)

async def main(connection):
    # Set color scheme correctly at app start
    app = await iterm2.async_get_app(connection)
    parts = await app.async_get_theme()
    await changeTheme(parts, connection)

    async with iterm2.VariableMonitor(connection, iterm2.VariableScopes.APP, "effectiveTheme", None) as mon:
        while True:
            # Block until theme changes
            theme = await mon.async_get()
            parts = theme.split(" ")
            await changeTheme(parts, connection)


iterm2.run_forever(main)

Change Dark Background and Light Background to color presets you like.

2. Enabled switch_automatic.py from Scripts menu.