How do I stash only one of the multiple changed files on my branch?
git stash push -p -m "my commit message"
-p let's you select the hunks that should be stashed; whole files can be selected as well.
You'll be prompted with a few actions for each hunk:
y - stash this hunk
n - do not stash this hunk
q - quit; do not stash this hunk or any of the remaining ones
a - stash this hunk and all later hunks in the file
d - do not stash this hunk or any of the later hunks in the file
g - select a hunk to go to
/ - search for a hunk matching the given regex
j - leave this hunk undecided, see next undecided hunk
J - leave this hunk undecided, see next hunk
k - leave this hunk undecided, see previous undecided hunk
K - leave this hunk undecided, see previous hunk
s - split the current hunk into smaller hunks
e - manually edit the current hunk
? - print help