how to find change in file using git bisect code example
Example: git bisect
$ git bisect start
$ git bisect bad # Current version is bad
$ git bisect good v2.6.13-rc2 # v2.6.13-rc2 is known to be good
$ git bisect start
$ git bisect bad # Current version is bad
$ git bisect good v2.6.13-rc2 # v2.6.13-rc2 is known to be good