Deletes a git branch both locally and remotely. To use simply type: delete branch-name

git_branch_delete.sh

# Easily delete branches remotely and locally
# Simple type:
# delete feature-branch-name
function delete_branch() {
  log=$(git log origin/$1..$1 --oneline)
  if [[ -z "${log}" ]]; then
    git push origin :$1
    git branch -D $1
  elif [[ "${log}" == *"path not in the working tree"* ]]; then
    echo -e "\033[0;31mIt doesn't appear that your branch exists remotely."
    tput sgr0
    while true; do
      read -p "Are you sure you want to delete this branch? [y/n] `echo $'\n> '`" yn
      case $yn in
        [Yy]* ) git push origin :$1; git branch -D $1; break;;
        [Nn]* ) break;;
        * ) echo "Please answer Yes or No.";;
      esac
    done
  else
    echo -e "\033[0;31mYour local branch: $1 has commits that have not been pushed:"
    echo -e "\033[0;33m${log}"
    tput sgr0
    while true; do
      read -p "Are you sure you want to delete this branch? [y/n] `echo $'\n> '`" yn
      case $yn in
        [Yy]* ) git push origin :$1; git branch -D $1; break;;
        [Nn]* ) break;;
        * ) echo "Please answer Yes or No.";;
      esac
    done
  fi
}

function delete() {
  branch=$1
  if [[ -z "$branch" ]]; then
    echo -e "\033[0;31mNo branch given. Please specify a branch to delete:"
    tput sgr0
    echo "(Type \"esc\" to stop branch deletion)"
    while true; do
      read -p "> " input
      case $input in
        esc | Esc | ESC ) break;;
        * ) delete_branch $input; break;;
      esac
    done
  else
    delete_branch $branch
  fi
}

Although git branch -d branch-name already tells you that you have unpushed commits, it doesn't allow you to delete the branch at that moment (without going back and using -D).

Accordingly, in this I've set up a way to check against remote to see if there are unpushed commits and warns you, but gives you the option of still deleting the branch.