git merge squash commits

git-merge-squash-commits.js

// http://stackoverflow.com/questions/5189560/squash-my-last-x-commits-together-using-git
# Reset the current branch to the commit just before the last 12:
git reset --hard HEAD~12

# HEAD@{1} is where the branch was just before the previous command.
# This command sets the state of the index to be as it would just
# after a merge from that commit:
git merge --squash HEAD@{1}

# Commit those squashed changes.  The commit message will be helpfully
# prepopulated with the commit messages of all the squashed commits:
git commit

# git reset --hard is not the end of the world. Use `git reflog` to reset again.
git reflog