Git hook to check for master change before allow to push

pre-push.sh

#!/bin/sh

# https://stackoverflow.com/questions/31992627/git-pre-commit-hook-error-color
# COLOR CODES
red='\033[0;41m'
white='\033[0;47m'
green='\033[0;32m'
yellow='\033[0;33m'
no_color='\033[0m'

# Fetch the latest refs for origin master
git fetch origin master

# Initialize the variables
UPSTREAM=origin/master
LOCAL=$(git rev-parse @)
REMOTE=$(git rev-parse "$UPSTREAM")
BASE=$(git merge-base @ "$UPSTREAM")

if [ $LOCAL == $REMOTE ]; then
    echo "${green} Great, Your branch is in sync with origin/master ${no_color}"
    exit 0
elif [ $LOCAL == $BASE ]; then
    echo "${red} You need to take the pull from the master, as master head has some new changes ${no_color}"
    exit 1
elif [ $REMOTE == $BASE ]; then
    echo "${green} Great, Your branch is in sync with master ${no_color}"
    exit 0
else
    echo "${red} Sorry your branch has diverged, take pull from origin/master to proceed the push ${no_color}"
    exit 1
fi