Overwrite pull

git fetch --all
git reset --hard origin/master

List of all the files changed in a commit

git ls-tree --name-only -r <commit-ish>

Git reset first commit

git update-ref -d HEAD

List all the conflicted files

git diff --name-only --diff-filter=U

Remove branches that have already been merged with master

git branch --merged | grep -v '\\*' | xargs -n 1 git branch -d