SYNOPSIS

git bisect start git bisect bad <rev> git bisect good <rev> git bisect reset [<branch>] git bisect visualize

DESCRIPTION

This command uses git-rev-list --bisect option to help drive the binary search process to find which change introduced a bug, given an old "good" commit object name and a later "bad" commit object name.

The way you use it is:

git bisect start
git bisect bad                  # Current version is bad
git bisect good v2.6.13-rc2     # v2.6.13-rc2 was the last version
                                # tested that was good

When you give at least one bad and one good versions, it will bisect the revision tree and say something like:

Bisecting: 675 revisions left to test after this

and check out the state in the middle. Now, compile that kernel, and boot it. Now, let's say that this booted kernel works fine, then just do

git bisect good                 # this one is good

which will now say

Bisecting: 337 revisions left to test after this

and you continue along, compiling that one, testing it, and depending on whether it is good or bad, you say "git bisect good" or "git bisect bad", and ask for the next bisection.

Until you have no more left, and you'll have been left with the first bad kernel rev in "refs/bisect/bad".

Oh, and then after you want to reset to the original head, do a

git bisect reset

to get back to the master branch, instead of being in one of the bisection branches ("git bisect start" will do that for you too, actually: it will reset the bisection state, and before it does that it checks that you're not using some old bisection branch).

During the bisection process, you can say

git bisect visualize

to see the currently remaining suspects in gitk.

Author

Written by Linus Torvalds <torvalds@osdl.org>

Documentation

Documentation by Junio C Hamano and the git-list <git@vger.kernel.org>.

GIT

Part of the git suite