Yesterday we dealt with some git commands which allow it to be used as originally intended. Today we’ll move on to some powerful, but dangerous commands which (almost) literally allow developers to rewrite history.
The basic command is
git rebase -i commit_identifier
This will bring up a list in your famourite text editors of all commits between the one named and the current head. For example:
pick 90d76c1 Add ShowCVs filter to the paraview plugins page.
pick 5b9017f Blogging some git recipes.
pick 8f6c9b0 Another blog post on git.
# Rebase 533d109..8f6c9b0 onto 533d109 (3 command(s))
# p, pick = use commit
# r, reword = use commit, but edit the commit message
# e, edit = use commit, but stop for amending
# s, squash = use commit, but meld into previous commit
# f, fixup = like "squash", but discard this commit's log message
# x, exec = run command (the rest of the line) using shell
# These lines can be re-ordered; they are executed from top to bottom.
# If you remove a line here THAT COMMIT WILL BE LOST.
# However, if you remove everything, the rebase will be aborted.
# Note that empty commits are commented out
The commented lines at the bottom provide a note memoir on what can be done. Effectively the incremental changes listed can be
The last option is particularly suitable for hiding bug fixes from the outside world.
Another version of the rebase command
git rebase --autosquash -i
Scans the log of commit messages and sets commits which begin like squash!5b9017f or fixup!5b9017f in correct position and with the relevant option. A new commit can also be set with this option by using one of the forms
git commit --squash 123456
git commit --fixup 123456