Ubuntu 12.04 LTS Server 64My unattended-mode bootstrap.sh script contains:apt-get upgrade -yI know that during execution a primitive UI for GRUB installation will be shown which requires entering keypress sequence:up arrow space bar enter/returnIs it possible to pipe this sequence, something like:echo key1 key2 key3 | apt-get upgrade -y
Ubuntu unattended install : echo keypress to dialog
bash;ubuntu;scripting;echo