$  vim MASTER
$  git add .
$  git commit -m m1
[master 8f78730] m1
 1 file changed, 1 insertion(+)
 create mode 100644 MASTER

$  vim MASTER
$  git add .
$  git commit -m m2
[master 591a601] m2
 1 file changed, 1 insertion(+)