Squash several Git commits into a single commit

squash.sh

git checkout master
git fetch 
git pull

# Merge the feature branch into the master branch.
git merge FEATURE/demo

# Reset the master branch to origin's state.
git reset origin/master

# Git now considers all changes as unstaged changes.
# We can add these changes as one commit.
# Adding . will also add untracked files.
git add --all
git commit