Bash script to poll Github and rebuild and restart a jekyll site

update-jekyll

#!/bin/sh
#This is a simple bash script that will poll github for changes to your repo,
#if found pull them down, and then rebuild and restart a Jekyll site running 
#in Nginx. Note, we cannot use cron to schedule a job every 5 seconds, so we create
#a script that executes an infinite loop that sleeps every 5 seconds
#We run the script with nohup so it executes as a background process: $nohup ./update-jekyll

while true
do

#move into your git repo where your jekyll site is
cd ~/a_folder_created_off_home/the_git_repo_folder_you_cloned_in;

git fetch;
LOCAL=$(git rev-parse HEAD);
REMOTE=$(git rev-parse @{u});

#if our local revision id doesn't match the remote, we will need to pull the changes
if [ $LOCAL != $REMOTE ]; then
    #pull and merge changes
    git pull origin master;

    #build the new site, you must install jekyll on the server, alternatively you could put the built _site
    #repo under version control and just update based off the changes in that folder. Jekyll outputs build into /_site
    jekyll build;

    #change back to home directory 
    cd
    
    sudo service nginx stop
    
    #remove current site directory
    sudo rm -rf /var/www/site.com/public_html;

    #copy the newly built site into the directory nginx will serve it from
    sudo cp -r a_folder_created_off_home/the_git_repo_folder_you_cloned_in/_site /var/www/site.com/public_html
    
    sudo service nginx start;
fi
sleep 5
done