Retrieving lost Git commits

From time to time I've managed to "lose" commits in Git, usually after I have initialised a submodule in a project and forgot to checkout a specific branch before committing changes. When I eventually do realise my mistake, I need to get those commits back into the relevant branch - in this case, master. Here's how it's done.

git reflog

This command will return something like:

902532b HEAD@{5}: commit: Doing some stuff on master now...wait where's my previous commits?
7f6c682 HEAD@{7}: checkout: moving from 3a311d8f746f903e15ce145a3e7683e0d53536fb to master
3a311d8 HEAD@{8}: commit: Added some more stuff
56f7716 HEAD@{9}: commit: Added some stuff
7f6c682 HEAD@{10}: checkout: moving from master to 7f6c6821c80baff91492af4909f1012876ef6249

56f7716 and 3a311d8 are the SHA identifiers of the commits that are floating around in the git void, attached to no branch, so I want to move them into the master branch. Starting with the first commit:

git checkout 56f7716

This will return output similar to:

Note: moving to '56f7716' which isn't a local branch
If you want to create a new branch from this checkout, you may do so
(now or later) by using -b with the checkout command again. Example:
git checkout -b
HEAD is now at 56f7716... Added some stuff

Pretty self explanatory. Let's do what it suggests and create a branch at this point in the history tree. We can then merge that branch into master (or whichever branch it belongs to).

git checkout -b temp_branch
git checkout master
git merge temp_branch

The commit is now in master where it belongs. Rinse and repeat for commit 3a311d8 and all is well in the world again!