git stash

git  init --quiet repo
cd   repo

'foo 1
foo 2
foo 3
foo 4
foo 5
'       > foo.txt

'bar 1
bar 2
bar 3
bar 4
bar 5
'        > bar.txt

git add *
git commit --quiet -m 'add file.foo, file.bar'

sed -i 's/bar 2/bar two/'   bar.txt
git commit --quiet . -m "change line 2 in bar.txt"

'foo 6
'           >> foo.txt

git stash

sed -i 's/bar 5/bar five/'  bar.txt
git commit --quiet . -m "Urgent fix in bar.txt"

git stash pop

git commit . --quiet -m "add foo 6"