Checkout to a base branch (master, develop etc.) and merges to your current branch

merge_branches.sh

#!/bin/bash

function usage()
{
    printf "Usage:\n\n"
    printf "./merge_branches.sh <branch>\n\n"
}

if [ "$1" == "" ]; then
    usage
    exit 0
fi

source_branch="$(git branch | grep \* | cut -d ' ' -f2)"
dest_branch=$1

git checkout $dest_branch;
git pull -p;
git checkout $source_branch;
git merge $dest_branch --no-ff;