git-fold

#! /bin/sh

# git-fold (a k a "git fold") fetches the main branch upstream,
# and if your current branch has already been landed upstreams,
# then check out the master branch, delete the landed branch,
# and catch up master with origin

# optional reference branch to check folding against and move to - or master
master="${1:-master}"

# optional reference origin to fetch from and pull up to
origin="${2:-origin}"
git fetch "$origin"

branch="$(git symbolic-ref --short HEAD)"
delete="$(git branch --merged "${origin}/${master}" \
  | cut -b 3- \
  | egrep -v "^${master}$" \
  | egrep "^${branch}$")"

if [ -n "$delete" ]; then
  git checkout "$master"
  git branch -d "$delete"
  git pull --ff-only
fi

Nice! I have a version I called git close-pr that didn't do as good a job finding the parent branch. Suggestion: add a call to git remote prune $origin to the end, and make the first line #!/bin/sh -e