GNOME Ubuntu center dock code example
Example 1: dconf editor ubuntu 20.04
sudo apt-get update
sudo apt-get install dconf-editor
Example 2: customize dock in ubuntu
$ gsettings set org.gnome.shell.extensions.dash-to-dock extend-height false
$ gsettings set org.gnome.shell.extensions.dash-to-dock dock-position BOTTOM
$ gsettings set org.gnome.shell.extensions.dash-to-dock transparency-mode FIXED
$ gsettings set org.gnome.shell.extensions.dash-to-dock dash-max-icon-size 64
$ gsettings set org.gnome.shell.extensions.dash-to-dock unity-backlit-items true