simple squash without rebase

gistfile1.txt

## within current branch, squashes all commits that are ahead of master down into one
## useful if you merged with upstream in the middle of your commits (rebase could get very ugly if this is the case)
 
## commit any working changes on branch "mybranchname", then...
git checkout master
git checkout -b mybranchname_temp
git merge --squash mybranchname
git commit -am "Message describing all squashed commits"
git branch -m mybranchname mybranchname_unsquashed
git branch -m mybranchname
 
## optional, not recommended if you want to keep the unsquashed history around for a bit longer
git branch -D mybranchname_unsquashed
 
## if squashing already-pushed commits...
git push --force