Update a local git repo by switching to master, fetching all remotes, deleting all local branches that track a remote branch that's now gone, fast forward merge upstream into local master and push local master to origin

update-repo.sh

#!/bin/bash -e

# https://gist.github.com/gene1wood/ddd66d79fc472f351a04c643aecbcf75

log() {
  echo -e "\e[92m${1}\e[0m"
}

if ! git status >/dev/null 2>&1; then
  log "Must be in a git repo"
  exit 1
fi

UPSTREAM_REMOTE=upstream
ORIGIN_REMOTE=origin
DEFAULT_BRANCH=$(git remote show origin | sed -n '/HEAD branch/s/.*: //p')

log "Checking out $DEFAULT_BRANCH"
git checkout "$DEFAULT_BRANCH"

for remote in $(git remote); do
  log "Fetching remote $remote"
  git fetch --progress --prune --recurse-submodules=no "$remote"
done

log "Deleting any local branches which are tracking remote branches that no longer exist"
LANG=en git branch --format='%(if:equals=gone)%(upstream:track,nobracket)%(then)%(refname:short)%(end)' | grep '.' | xargs --no-run-if-empty git branch -D

if git remote get-url $UPSTREAM_REMOTE >/dev/null 2>&1; then
  log "Fast forward merging $UPSTREAM_REMOTE into our local ${DEFAULT_BRANCH}"
  git merge --no-commit --ff ${UPSTREAM_REMOTE}/${DEFAULT_BRANCH}
else
  log "There is no ${UPSTREAM_REMOTE} remote. Skipping fast forward merge of ${DEFAULT_BRANCH}"
fi
if git remote get-url $ORIGIN_REMOTE >/dev/null 2>&1; then
  log "Pushing ${DEFAULT_BRANCH} to $ORIGIN_REMOTE"
  git push --porcelain --progress $ORIGIN_REMOTE refs/heads/${DEFAULT_BRANCH}:refs/heads/${DEFAULT_BRANCH}
else
  log "There is no $ORIGIN_REMOTE remote. Skipping push of ${DEFAULT_BRANCH}"
fi