Git squash

git-squash.sh

#!/bin/bash -e
# Go back to the last commit that we want to form the initial commit (detach HEAD)
branch=$(git branch --no-color 2> /dev/null | sed -e '/^[^*]/d' -e 's/* \(.*\)/\1/')
tag="tmp-$RANDOM"

git checkout HEAD

# reset the branch pointer to the initial commit,
# but leaving the index and working tree intact.
git reset --soft HEAD~1

# amend the initial tree using the tree from 'B'
git commit --amend

# temporarily tag this new initial commit
# (or you could remember the new commit sha1 manually)
git tag $tag

# go back to the original branch
git checkout $branch

# Replay all the commits after B onto the new initial commit
git rebase --onto $tag HEAD

# remove the temporary tag
git tag -d $tag