a couple quick git tips

The other day someone asked in #git how to fix something in the middle of an unsuccessful rebase. So, I thought I'd rebase some of my own code, reorder things so there must be a conflict, and then try to duplicate their question.

Only problem was that there was no error, and I hadn't really paid attention to which commits I reordered. Thankfully, I got a bit of help from a gent named doener.

I'm including a rather long gist showing the process. Basically, git reflog is your friend, and you should play with this at some point in a test repo like I've done here.

Note: anytime you git reset --hard be very sure and confident of what you're doing.

	> mkdir undo-rebase
	~ > cd !$
	cd undo-rebase
	~/undo-rebase > git init
	Initialized empty Git repository in .git/
	~/undo-rebase master > touch one
	~/undo-rebase master > ga .
	~/undo-rebase master > gc -m "one"
	Created initial commit 3dfffad: one
	0 files changed, 0 insertions(+), 0 deletions(-)
	create mode 100644 one
	~/undo-rebase master > touch two
	~/undo-rebase master > ga .
	~/undo-rebase master > gc -m "two"
	Created commit 0c36fd9: two
	0 files changed, 0 insertions(+), 0 deletions(-)
	create mode 100644 two
	~/undo-rebase master > touch three
	~/undo-rebase master > ga .
	~/undo-rebase master > gc -m "three"
	Created commit 6c4a8e8: three
	0 files changed, 0 insertions(+), 0 deletions(-)
	create mode 100644 three
	~/undo-rebase master > gl
	...
	commit 6c4a8e844de2809b23710fe84080187d7c6c89a6
	Author: Jack Dempsey <jack.dempsey@gmail.com>
	Date: Thu Jul 16 22:40:00 2009 -0400
	three
	commit 0c36fd9b1cf3bbc4ad29de5a62e4114465c307b3
	Author: Jack Dempsey <jack.dempsey@gmail.com>
	Date: Thu Jul 16 22:39:54 2009 -0400
	two
	commit 3dfffad2749dea6a187a32f7dd20fa4c13db452b
	Author: Jack Dempsey <jack.dempsey@gmail.com>
	Date: Thu Jul 16 22:39:46 2009 -0400
	one
	~/undo-rebase master > git rebase -i head^^
	...
	pick 0c36fd9 two
	pick 6c4a8e8 three
	# Rebase 3dfffad..6c4a8e8 onto 3dfffad
	#
	# Commands:
	# pick = use commit
	# edit = use commit, but stop for amending
	# squash = use commit, but meld into previous commit
	#
	# If you remove a line here THAT COMMIT WILL BE LOST.
	# However, if you remove everything, the rebase will be aborted.
	#
	~/undo-rebase master > gl
	...
	commit 39521f7ed570f31b778b4281072131e72ada4c82
	Author: Jack Dempsey <jack.dempsey@gmail.com>
	Date: Thu Jul 16 22:39:54 2009 -0400
	two
	commit e0014a06d12f966bf0d332a0e07cbd8c1ecff21c
	Author: Jack Dempsey <jack.dempsey@gmail.com>
	Date: Thu Jul 16 22:40:00 2009 -0400
	three
	commit 3dfffad2749dea6a187a32f7dd20fa4c13db452b
	Author: Jack Dempsey <jack.dempsey@gmail.com>
	Date: Thu Jul 16 22:39:46 2009 -0400
	one
	~/undo-rebase master > ZOMG wait wait wait
	~/undo-rebase master > git reflog show master@{1}
	6c4a8e8... master@{1}: commit: three
	0c36fd9... master@{2}: commit: two
	3dfffad... master@{3}: commit (initial): one
	~/undo-rebase master > git reset 6c4a8e8 --hard
	HEAD is now at 6c4a8e8 three
	commit 6c4a8e844de2809b23710fe84080187d7c6c89a6
	Author: Jack Dempsey <jack.dempsey@gmail.com>
	Date: Thu Jul 16 22:40:00 2009 -0400
	three
	commit 0c36fd9b1cf3bbc4ad29de5a62e4114465c307b3
	Author: Jack Dempsey <jack.dempsey@gmail.com>
	Date: Thu Jul 16 22:39:54 2009 -0400
	two
	commit 3dfffad2749dea6a187a32f7dd20fa4c13db452b
	Author: Jack Dempsey <jack.dempsey@gmail.com>
	Date: Thu Jul 16 22:39:46 2009 -0400
	one
	Voila!

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