git init

echo base content > file

git add file
git commit -m"Initial"
git branch other

echo "Big Bad Bug is here" >> file
git commit -am"Add bug"

echo base content > file
git commit -am"Whew, removed big bad bug"

git checkout other
echo "Big Bad Bug is here" >> file
git commit -am"Independently add bug"

git merge master
grep Bug file && echo Git added bug