Script to check whether local branch and the origin's counterpart are in sync

git-origin-branch-sync-status.sh

###
# Returns a code that determine whether local branch and its origin's counterpart
# are in sync. In sync, in this case, means there's no commits in local branch
# that have not been pushed to the origin. In short, it means the following
# command returns nothing.
#
# 		git log {branch} --not origin/{branch}
#
# The code will be be in `$?` variable after the funciton call.
# The status code can be:
#  - 0: local and origin are in sync
#  - 1: the folder is not a git repository
#  - 2: local and origin are not in sync
###
function getOriginSyncStatus() {
	# This line is used just for checking whether
	# the folder is a git repos or not. 
	# Output and error are muted.
	git branch 1> /dev/null 2> /dev/null

	# Check the status code of the line above
	if [ $? -ne 0 ]; then
		return 1
	else
		BRANCH=`git branch 2> /dev/null | grep \* | awk '{print $2}'`

		OUTPUT=`git log $BRANCH --not origin/$BRANCH`
		if [ "$OUTPUT" == "" ]; then
			return 0
		else
			return 1
		fi
	fi
}

###
# Starting point
###

COLOR_RESET="\033[0m"
COLOR_ERROR="\033[31m"
COLOR_WARNING="\033[33m"
COLOR_SUCCESS="\033[32m"

# Empty newline
echo

# Get the function 
# The return code will be stored in `$?`
getOriginSyncStatus

case $? in
	0) 
		echo "${COLOR_SUCCESS}Yay! ${BRANCH} local and origin are in sync.${COLOR_RESET}";;
	1) 
		echo "${COLOR_ERROR}This is not a git repository.${COLOR_RESET}";;
	2) 
		echo "${COLOR_WARNING}Wait! ${BRANCH} local and origin are NOT in sync.${COLOR_RESET}";;
esac

# Empty newline
echo