How to amend older Git commit? [duplicate]

Answer 1

I prepared my commit that I wanted to amend with an older one and was surprised to see that rebase -i complained that I have uncommitted changes. But I didn't want to make my changes again specifying edit option of the older commit. So the solution was pretty easy and straightforward:

1. prepare your update to older commit, add it and commit
2. git rebase -i ^ - notice the ^ so you see the said commit in the text editor

3. you will get sometihng like this:

   pick 8c83e24 use substitution instead of separate subsystems file to avoid jgroups.xml and jgroups-e2.xml going out of sync
   pick 799ce28 generate ec2 configuration out of subsystems-ha.xml and subsystems-full-ha.xml to avoid discrepancies
   pick e23d23a fix indentation of jgroups.xml
   

4. now to combine e23d23a with 8c83e24 you can change line order and use squash like this:

   pick 8c83e24 use substitution instead of separate subsystems file to avoid jgroups.xml and jgroups-e2.xml going out of sync    
   squash e23d23a fix indentation of jgroups.xml
   pick 799ce28 generate ec2 configuration out of subsystems-ha.xml and subsystems-full-ha.xml to avoid discrepancies
   

5. write and exit the file, you will be present with an editor to merge the commit messages. Do so and save/exit the text document

6. You are done, your commits are amended

credit goes to: http://git-scm.com/book/en/Git-Tools-Rewriting-History There's also other useful demonstrated git magic.