blob
mark :1
data 6
alpha

reset refs/heads/master
commit refs/heads/master
mark :2
author A U Thor <author@example.com> 1167600600 +0230
committer C O Mitter <committer@example.com> 1167600600 +0230
data 10
add alpha
M 100644 :1 alpha

blob
mark :3
data 5
alpha
commit refs/heads/master
mark :4
author A U Thor <author@example.com> 1167600600 +0230
committer C O Mitter <committer@example.com> 1167600600 +0230
data 9
add beta
from :2
M 120000 :3 beta