git-unpushed-branches

#!/bin/bash
# Usage: git unpushed-branches
#
# Show unmerged branches that don't have a corresponding branch on the origin remote.
set -e

[ "$1" = "-h" ] && exec sed -ne '/^#/!q;s/.\{1,2\}//;1d;p' < "$0"

for REMOTE in upstream origin; do
  MASTER="$(git symbolic-ref --short "refs/remotes/${REMOTE}/HEAD" 2>/dev/null)" && break
  MASTER="${REMOTE}/master"
done

git branch --no-merged "$MASTER" | cut -b3- | \
  while read -r branch; do
    upstream="$(git rev-parse --symbolic-full-name "${branch}@{upstream}" 2>/dev/null || true)"
    [ "$upstream" != "refs/remotes/${MASTER}" ] || upstream=""
    if [ -z "$upstream" ] && ! git rev-parse --verify --quiet "${REMOTE}/${branch}" >/dev/null; then
      echo "$branch"
    fi
  done