Bash script to toggle / change Gnome and Shell themes and Terminal profiles between dark and light modes

auto-toggle-theme.sh

#!/bin/bash

# Cron doesn't have access to env.vars as your user has,
# so we need to export these:
export TERM=xterm-256color
# Check current value with: 'echo $DBUS_SESSION_BUS_ADDRESS' and paste here
# see: https://stackoverflow.com/questions/53628122/git-libsecret-throws-cannot-autolaunch-d-bus-without-x11-display
export DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus


# ===========================================================
# To be used with cron:
# Check every hour and change theme depending on the time.
# Create a crontab (i.e.: crontab -e)
#
# i.e:
#
# 0 * * * * /home/jose/bin/auto-toggle-theme.sh
# ===========================================================


# Import the theme setting functions
. /home/jose/bin/toggle-theme.sh --source-only


maybe-toggle-theme() {
    light_time=$1
    current_gtk_theme=$(get-gtk-theme)
    say @magenta "Current theme: @b@magenta $current_gtk_theme (light mode: $light_time)"

    if [[ $current_gtk_theme != "'$GTK_DARK'" ]] && [[ $light_time == "nightlight" ]];
    then
        say @blue "Switching to DARK mode:"
        set-dark
    elif [[ $current_gtk_theme != "'$GTK_LIGHT'" ]] && [[ $light_time == "daylight" ]];
    then
        say @yellow "Switching to LIGHT mode:"
        set-light
    fi
}

# Get current time
current_time=$(date +'%T')
say @magenta "Current time: $current_time"


if [[ $current_time > '07:00' ]] && [[ $current_time < '20:00' ]];
then
    maybe-toggle-theme "daylight"
# elif [[ condition ]]; then
#     #statements
else
    maybe-toggle-theme "nightlight"
fi

toggle-gnome-theme.sh

#!/bin/bash

set -e
set -o pipefail


# Some useful commands to figure out what to tweak:
# https://askubuntu.com/questions/971067/how-can-i-script-the-settings-made-by-gnome-tweak-tool#971577
# * watch dconf changes being made:
#   'dconf watch /'
# * List gsettings keys:
#   'gsettings list-keys org.gnome....'

# https://stackoverflow.com/questions/41156442/glib-gio-message-using-the-memory-gsettings-backend-happened-in-ubuntu-16-10
export GIO_EXTRA_MODULES=/usr/lib/x86_64-linux-gnu/gio/modules/

# Gnome Terminal themes
# Avaialable at: http://mayccoll.github.io/Gogh/ (https://github.com/Mayccoll/Gogh)
# After installing or creating the desired terminal themes;
# 1. Retrieve the ID: `dconf dump /org/gnome/terminal/legacy/profiles:/ | awk '/\[:/||/visible-name=/'`
# 2. Set which one to use for Dark and Light mode.
TERMINAL_LIGHT=b0c17716-3330-4773-a48e-6051c785e449  # Pencil Light
TERMINAL_DARK=7d341320-cabf-4ad3-91de-275e800647eb   # Sweet Terminal

# GTK3 Themes
# Orchis: https://github.com/vinceliuice/Orchis-theme
#
# MacOS 11: https://www.pling.com/p/1220826
# MacOS Sierra: https://www.pling.com/p/1013714
# MacOS Mojave: https://www.pling.com/p/1275087
# MacOS WhiteSur: https://github.com/vinceliuice/WhiteSur-gtk-theme
#
# For a complete article on the topic: https://itsfoss.com/make-ubuntu-look-like-macos/
#
# NOTE: Themes should be installed first. i.e.: Copied to ~/.themes
GTK_LIGHT='Orchis-Light-Compact'   # Or  'macOS11-GTK' | 'WhiteSur-light-blue'
GTK_DARK='Orchis-Dark-Compact'     # Or  'Mojave-dark' | 'WhiteSur-dark-blue'

# Similar to the above but for the Gnome Shell (i.e.: top desktop bar, ...)
SHELL_LIGHT='Orchis-Light-Compact' # Or  'macOS11-Shell'      | 'WhiteSur-light-blue'
SHELL_DARK='Orchis-Dark-Compact'   # Or  'macOS11-Shell-Dark' | 'WhiteSur-dark-blue'

# Similar to the above but for OhMyBash themme (i.e.: bash prompt)
OSH_LIGHT='powerline-light'       # Or  'powerline-jmrf'
OSH_DARK='powerline-light'        # Or  'cupcake'


say() {
 echo "$@" | sed \
         -e "s/\(\(@\(red\|green\|yellow\|blue\|magenta\|cyan\|white\|reset\|b\|u\)\)\+\)[[]\{2\}\(.*\)[]]\{2\}/\1\4@reset/g" \
         -e "s/@red/$(tput setaf 1)/g" \
         -e "s/@green/$(tput setaf 2)/g" \
         -e "s/@yellow/$(tput setaf 3)/g" \
         -e "s/@blue/$(tput setaf 4)/g" \
         -e "s/@magenta/$(tput setaf 5)/g" \
         -e "s/@cyan/$(tput setaf 6)/g" \
         -e "s/@white/$(tput setaf 7)/g" \
         -e "s/@reset/$(tput sgr0)/g" \
         -e "s/@b/$(tput bold)/g" \
         -e "s/@u/$(tput sgr 0 1)/g"
}

# =============================================
# ================ Gnome Shell ================
set-shell-theme() {
    theme=$1
    say @blue "Setting SHELL theme to: @b$theme"
    # gsettings doesn't have a scheme for this, so we use dconf directly
    dconf write /org/gnome/shell/extensions/user-theme/name "'$theme'"
}

get-shell-theme() {
    echo $(gsettings get org.gnome.shell.extensions.user-theme name)
}

# =============================================
# ================ GTK Theme ==================

set-gtk-theme() {
    theme=$1
    say @blue "Setting GTK theme to: @b $theme"
    gsettings set org.gnome.desktop.interface gtk-theme $theme
}

get-gtk-theme() {
    echo $(gsettings get org.gnome.desktop.interface gtk-theme)
}

# =============================================
# ================ Terminal ===================
set-terminal-profile() {
    theme=$1
    say @blue "Setting TERMINAL theme to: @b$theme"
    gsettings set org.gnome.Terminal.ProfilesList default $theme
}

get-terminal-profile() {
    # dconf dump /org/gnome/terminal/legacy/profiles:/ | awk '/\[:/||/visible-name=/'
    echo $(gsettings get org.gnome.Terminal.ProfilesList default)
}

swap-osh-theme() {
    current=$1
    next=$2
    sed -i "s/^OSH_THEME=\""$current\""/OSH_THEME=\""$next\""/g" /home/$USER/.bashrc
}

set-light() {
    set-gtk-theme $GTK_LIGHT
    set-shell-theme $SHELL_LIGHT
    set-terminal-profile $TERMINAL_LIGHT
    swap-osh-theme $OSH_DARK $OSH_LIGHT
}

set-dark() {
    set-gtk-theme $GTK_DARK
    set-shell-theme $SHELL_DARK
    set-terminal-profile $TERMINAL_DARK
    swap-osh-theme $OSH_LIGHT $OSH_DARK
}

toggle-theme() {
    current_gtk_theme=$(get-gtk-theme)
    say @blue "Current theme: @b@magenta $current_gtk_theme"

    if [ $current_gtk_theme = "'$GTK_LIGHT'" ];
    then
        say @blue "Switching to DARK mode:"
        set-dark
    else
        say @blue "Switching to LIGHT mode:"
        set-light
    fi
}

# Toggle between Light & Dark
if [ "${1}" != "--source-only" ]; then
    # main "${@}"
    toggle-theme
fi

toggle-kde-theme.sh

#!/bin/bash

set -e
set -o pipefail

# List the installed themes with: 'lookandfeeltool -l org.kde.breezedark.desktop'
KDE_LIGHT_THEME="org.kde.breeze.desktop"
KDE_DARK_THEME="org.kde.breezedark.desktop"

# List of currently existing profiles with: 'konsole --list-profiles'
KONSOLE_LIGHT_THEME="Light"
KONSOLE_DARK_THEME="Dark"

cprint() {
 	echo "$@" | sed \
         -e "s/\(\(@\(red\|green\|yellow\|blue\|magenta\|cyan\|white\|reset\|b\|u\)\)\+\)[[]\{2\}\(.*\)[]]\{2\}/\1\4@reset/g" \
         -e "s/@red/$(tput setaf 1)/g" \
         -e "s/@green/$(tput setaf 2)/g" \
         -e "s/@yellow/$(tput setaf 3)/g" \
         -e "s/@blue/$(tput setaf 4)/g" \
         -e "s/@magenta/$(tput setaf 5)/g" \
         -e "s/@cyan/$(tput setaf 6)/g" \
         -e "s/@white/$(tput setaf 7)/g" \
         -e "s/@reset/$(tput sgr0)/g" \
         -e "s/@b/$(tput bold)/g" \
         -e "s/@u/$(tput sgr 0 1)/g"
}


# =============================================
# ================ KDE Theme ==================
get-kde-theme() {
    curremt_theme=$(grep 'LookAndFeelPackage=' ~/.config/kdeglobals | awk -F'=' '{print $2}')
    echo $curremt_theme
}

set-kde-theme() {
    theme=$1
    cprint @blue "Setting KDE theme to: @b $theme"
    lookandfeeltool -a $theme
}

# =============================================
# ============== Konsole Theme ================
switch-konsole-profile() {
    # NOTE: This requires the Konsole profile to exist and configured as a LIght/Dark theme.
    # NOTE: Requires qdbus: 'sudo dnf install qt5-qttools'
    profile=$1
    cprint @blue "Setting Konsole profile to: @b $profile"
    # This changes the default profile for every Konsole window from here onward
    qdbus org.kde.konsole $KONSOLE_DBUS_SESSION org.kde.konsole.Session.setProfile $profile
    
    # This iterates over the open Konsole instances and changes to the desired profile
    for instance in $(qdbus-qt6 | grep org.kde.konsole); do
      # Iterate over all sessions within each instance
      for session in $(qdbus-qt6 "$instance" | grep -E '^/Sessions/'); do
        # Set the profile for each session
        qdbus-qt6 "$instance" "$session" org.kde.konsole.Session.setProfile "$profile"
      done
    done
}


toggle-theme() {
    current_gtk_theme=$(get-kde-theme)
    cprint @blue "Current theme: @b@magenta $current_gtk_theme"

    if [[ $current_gtk_theme == $KDE_LIGHT_THEME ]];
    then
        cprint @blue "Switching to DARK mode"
        set-kde-theme $KDE_DARK_THEME
        switch-konsole-profile $KONSOLE_DARK_THEME
    else
        cprint @blue "Switching to LIGHT mode"
        set-kde-theme $KDE_LIGHT_THEME
        switch-konsole-profile $KONSOLE_LIGHT_THEME
    fi
}

Some useful resources

• Awesome answer for debugging crontabs: crontab-not-running
• crontab guru

To run the auto-toggle-theme.sh at login

Add in ~/.profile:

bash $HOME/bin/auto-toggle-theme.sh > /dev/null 2>&1

To run the auto-toggle-theme.sh on resume:

⚠️: This might not work as dconf might not be connected

Create a new file @ /lib/systemd/system-sleep/resume-theme.sh, with:

#!/bin/sh

case $1/$2 in
  pre/*)
    echo "Going to $2..."
    # Place your pre suspend commands here, or `exit 0`
    # if no pre suspend action required
    exit 0
    ;;
  post/*)
    echo "Waking up from $2..."
    # Place your post suspend (resume) commands here, or `exit 0` 
    # if no post suspend action required
    /bin/bash /home/jose/bin/auto-toggle-theme.sh > /dev/null 2>&1
    ;;
esac

On Fedora with KDE the auto-toggle based on datetime can be achieved with: Koi