GDM Theme

You can change the GDM (lock/login screen) theme by replacing the default GNOME Shell theme.
However if it fails, your desktop environment may not operate correctly. So please be careful if doing this.

⚠️ Cautions:

• When applying this, other third-party GNOME Shell themes would look broken until you restore to the original theme.
• If GNOME Shell has been updated and restored to the original theme, you will need to install this again.

Requirements

You need to have the glib-compile-resources command. The package name depends on the distro:

• glib2 on Arch Linux
• glib2-devel on Fedora, openSUSE, etc.
• libglib2.0-dev on Debian, Ubuntu, etc.

For Ubuntu, you also need the libxml2-utils package.

Installation

1. Back up the original theme file. If you are already using a custom GDM theme, skip this:

sudo cp -av /usr/share/gnome-shell/gnome-shell-theme.gresource{,~}

For Ubuntu 17.10 or 18.04, you also need to back up the following file:

sudo cp -av /usr/share/gnome-shell/theme/ubuntu.css{,~}

For Ubuntu 18.10, you also need to back up the following file:

sudo cp -av /usr/share/gnome-shell/theme/Yaru/gnome-shell.css{,~}

2. Select a GTK+ theme to decide which variant to install.
3. Compile and replace the default theme file with the following commands:

GTK_THEME=$(gsettings get org.gnome.desktop.interface gtk-theme | sed "s/'//g")
cd /usr/share/themes/${GTK_THEME}/gnome-shell
sudo glib-compile-resources --target=/usr/share/gnome-shell/gnome-shell-theme.gresource gnome-shell-theme.gresource.xml

For Ubuntu 17.10 or 18.04, you also need the following command:

sudo cp -v gnome-shell.css /usr/share/gnome-shell/theme/ubuntu.css

For Ubuntu 18.10, you also need the following command:

sudo cp -v gnome-shell.css /usr/share/gnome-shell/theme/Yaru/gnome-shell.css

4. Reload the theme. If you are running GNOME Shell, press Alt + F2 then type rt.

Uninstallation

1. Restore to the original theme from the backup:

sudo mv -v /usr/share/gnome-shell/gnome-shell-theme.gresource{~,}

For Ubuntu 17.10 or 18.04, you also need the following:

sudo mv -v /usr/share/gnome-shell/theme/ubuntu.css{~,}

For Ubuntu 18.10, you also need the following:

sudo mv -v /usr/share/gnome-shell/theme/Yaru/gnome-shell.css{~,}

2. Reload the theme. If you are running GNOME Shell, press Alt + F2 then type rt.