git-downmerge

#!/bin/bash

set -e

# import dependency
parentPath=$( cd "$(dirname "${BASH_SOURCE[0]}")" ; pwd -P )
. "$parentPath/os-open"

# Check if params are enough to go ahead.
downmergeFrom=$1
downmergeTo=$2
test -z "$downmergeFrom" && echo "Please provide downmerge-from branch and downmerge-to branch." 1>&2 && exit 1
test -z "$downmergeTo" && echo "Please provide both downmerge-from as first argument branch and downmerge-to branch as the second argument." 1>&2 && exit 1

git fetch -p
git checkout -B sync/$downmergeTo
git reset --hard origin/$downmergeTo
git merge origin/$downmergeFrom
echo "resolve conflicts if any"
echo "then do git commit"
echo "and then git push origin sync/$downmergeTo"