Re: Programmatically edit the git rebase sequence?

["brian m. carlson" <sandals@crustytoothpaste.net>]

[-- Attachment #1: Type: text/plain, Size: 2243 bytes --]

On 2026-07-03 at 12:02:33, Matthias Beyer wrote:
> Hi git people,
> 
> in a recent conversation at work, the question of how to
> programmatically edit the git-rebase sequence came up.
> 
> Example use case:
> 
> I have a branch that touches a number of files, adds some files and
> removes some files.
> When rebasing, I want to split all commits that touched a certain subset
> of files, for the clearity of the history.
> 
> I look at the output of
> 
>     git log master..mybranch --oneline --diff-filter=M -- "./subdir/*.rs"
> 
> to find all commits in that subdir that only touched the files. All of
> these commits are to be "edit"ed.
> 
> Now I fire up `git rebase -i master` and manually(!) match the list from
> above `git-log` call and find the respective commits to edit them.
> 
> Is there a way I am not aware of to do that manual step programatically?
> Something like
> 
>     git rebase -i master --edit-commits="$(git log master..mybranch --diff-filter=M --format="%H" -- "./subdir/*.rs")"
> 
> would be convenient here, although I would understand if that is too
> much clutter for the already very heavy git CLI interface :-)

Yes, such a thing exists.  You want `GIT_SEQUENCE_EDITOR`, which is an
`EDITOR`-like command that edits the rebase list in place.  So tools
like `ed`, `ex`, `sed -i`, `perl -i`, or `ruby -i` would be useful here.

So you might want something like this (untested):

    GIT_SEQUENCE_EDITOR="perl -pi -e 's/^pick ($(git log master..mybranch --diff-filter=M --format="%h" -- "./subdir/*.rs" | paste -d '\''|'\'' -s -))/edit \$1/'" \
    git rebase -i master

Note the use of `%h`, since by default the object IDs are abbreviated.

If you want something simpler, you can also write a shell script which
edits the first argument in place and specify that.  Arbitrary shell is
allowed in `GIT_SEQUENCE_EDITOR`, much like in `EDITOR` and `VISUAL`.

I personally use this alias, which explicitly does not edit the sequence
list, to automatically squash in all squash and fixup commits without
prompting:

    srebase = "!f() { GIT_SEQUENCE_EDITOR=true git rebase -m -i --autosquash \"$@\"; };f"
-- 
brian m. carlson (they/them)
Toronto, Ontario, CA

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 325 bytes --]