forward.
+
However, there are cases in which your local changes do conflict with
the upstream changes, and `git pull` refuses to overwrite your
changes.  In such a case, you can stash your changes away,
perform a pull, and then unstash, like this:
+
----------------------------------------------------------------
$ git pull
 ...
file foobar not up to date, cannot merge.
$ git stash
$ git pull
$ git stash pop
----------------------------------------------------------------

Interrupted workflow::

When you are in the middle of something, your boss comes in and
demands that you fix something immediately.  Traditionally, you would
make a commit to a temporary branch to store your changes away, and
return to your original branch to make the emergency fix, like this:
+
----------------------------------------------------------------
# ... hack hack hack ...
$ git switch -c my_wip
$ git commit -a -m "WIP"
$ git switch master
$ edit emergency fix
$ git commit -a -m "Fix in a hurry"
$ git switch my_wip
$ git reset --soft HEAD^
# ... continue hacking ...
----------------------------------------------------------------
+
You can use 'git stash' to simplify the above, like this:
+
----------------------------------------------------------------
# ... hack hack hack ...
$ git stash
$ edit emergency fix
$ git commit -a -m "Fix in a hurry"
$ git stash pop
# ... continue hacking ...
----------------------------------------------------------------

Testing partial commits::

You can use `git stash push --keep-index` when you want to make two or
more commits out of the changes in the work tree, and you want to test
each change before committing:
+
----------------------------------------------------------------
# ... hack hack hack ...
$ git add --patch foo            # add just first part to the index
$ git stash push --keep-index    # save all other changes to the stash
$ edit/build/test first part
$ git commit -m 'First part'     # commit fully tested change
$ git stash pop