How to execute a shell script on your Raspberry PI?

• create a diretory for the script, for instance:
  sudo mkdir /home/pi/Code

• create a shell script with nano (or another editor):
  sudo nano /home/pi/Code/updatePI.sh
  

• example: the following shell script will update your RasPI:
  #!/bin/bash
  date
  echo UPDATING SYSTEM SOFTWARE – UPDATE
  sudo apt-get update
  echo UPDATING SYSTEM SOFTWARE – UPGRADE
  sudo apt-get upgrade
  echo UPDATING SYSTEM SOFTWARE – DISTRIBUTION
  sudo apt-get dist-upgrade
  echo REMOVING APPLICATION ORPHANS
  sudo apt-get autoremove –purge
  echo UPDATING FIRMWARE
  sudo rpi-update

• make your script executable:
  sudo chmod +x /home/pi/Code/updatePI.sh

• execute your script:
  sudo /home/pi/Code/updatePI.sh

• if you are in the directory where the script is located use:
  sudo ./updatePI.sh