Say your bug fix branch is called bugfix and you want to merge it into master:

git checkout master
git merge --squash bugfix
git commit

This will take all the commits from the bugfix branch, squash them into 1 commit, and merge it with your master branch.


Explanation :

git checkout master

Switches to your master branch.

git merge --squash bugfix

Takes all commits from the bugfix branch and groups it for a 1 commit with your current branch.
(no merge commit appears; you could resolve conflicts manually before following commit)

git commit

Creates a single commit from the merged changes.

Omitting the -m parameter lets you modify a draft commit message containing every message from your squashed commits before finalizing your commit.