ES01

#!/bin/bash
echo
sudo apt-get update
echo
echo '--------------------------------------------------------------------------------'
echo '--------------------------------------------------------------------------------'
echo
sudo apt-get -y -q upgrade
sudo rpi-update

#sudo apt-get -y -q dist-upgrade
#In Raspbian Wheezy a sudo apt-get update & dist-upgrade is sufficient.
#https://www.raspberrypi.org/forums/viewtopic.php?t=40553
#https://askubuntu.com/questions/81585/what-is-dist-upgrade-and-why-does-it-upgrade-more-than-upgrade
#   sudo rpi-update
#   Using rpi-update is no longer recommended as it installs a Testing Kernel.
#   https://www.raspberrypi.org/forums/viewtopic.php?t=40553

echo '--------------------------------------------------------------------------------'
echo '--------------------------------------------------------------------------------'
echo
echo "Making backup of config.txt before making changes."
echo
sudo cp /boot/config.txt /boot/config.txt.bak
echo
if grep -Fxq "gpu_mem = 32" /boot/config.txt ; then
  echo 'Using 32 MB of GPU Memory. No changes will be made.'
  echo "gpu_mem = 32" > /home/pi/Public/gpu_mem_temporary.txt
elif grep -Fxq "gpu_mem = 64" /boot/config.txt ; then
  echo 'Using 64 MB of GPU Memory currently, setting to 32 MB temporarily.'
  echo "gpu_mem = 64" > /home/pi/Public/gpu_mem_temporary.txt
  sudo sed -i '/gpu_mem = 64/ c\gpu_mem = 32' /boot/config.txt
elif grep -Fxq "gpu_mem = 128" /boot/config.txt ; then
  echo 'Using 128 MB of GPU Memory currently, setting to 32 MB temporarily.'
  echo "gpu_mem = 128" > /home/pi/Public/gpu_mem_temporary.txt
  sudo sed -i '/gpu_mem = 128/ c\gpu_mem = 32' /boot/config.txt
elif grep -Fxq "gpu_mem = 256" /boot/config.txt ; then
  echo 'Using 256 MB of GPU Memory currently, setting to 32 MB temporarily.'
  echo "gpu_mem = 256" > /home/pi/Public/gpu_mem_temporary.txt
  sudo sed -i '/gpu_mem = 256/ c\gpu_mem = 32' /boot/config.txt
else
  echo 'No value found, assuming using default 64 MB of GPU Memory'
  echo 'for the Raspberry Pi 3. Setting to 32 MB temporarily.'
  echo "gpu_mem = 64 - value not found" > /home/pi/Public/gpu_mem_temporary.txt
  sudo sh -c "echo 'gpu_mem = 32' >> /boot/config.txt"
fi

# add or replace "gpu_mem = 32"
# if you skip this step, you will probably get "out of memory" errors when compiling
# Instructions --> http://www.emulationstation.org/gettingstarted.html#install_rpi_standalone
echo '--------------------------------------------------------------------------------'
echo '--------------------------------------------------------------------------------'
echo
echo 'Part 1 completed, reboot and additional script to run automatically.'
echo 'Reboot to occur in 30 seconds. After part 2 is completed, your Pi'
echo 'will reboot again. It creates a script noted below that will not'
echo 'be automatically deleted. You may delete this after the second'
echo 'reboot occurs.'
echo

sudo reboot