How to modify a file in your local git commit history with git rebase (with Vscode Ide)?

situation

• I have a big file src\build_llm_learn\p7_digitalsreeni_210_unet_segmentation_models\model_examine\model_exec.ipynb in my local git commit history.
  Its file size is 160mb.

  • (also another file examine_main.ipynb).

• I want to manually go to each commit point,
  
  to remove that file, or to modify the file to reduce its size,
  
  for each of the commit point in the git history.

procedure

create a backup branch

• create a backup branch:

  git branch backup-before-cleanup

git rebase

• In vscode git panel, get the init commit hash.

• Open git bash CLI.

• git rebase to that point.
  

  git rebase -i 75eedea9e6bf96a62ac7f2f8392de48b7660f8c5^

mark commits for editing

• An editor will open with a list of your last commits, something like this:

  pick 75eedea First commit with the big file
  pick b2c3d4e Second commit, more changes
  pick c3d4e5f ...
  pick 3c4d5e6 ...
  pick 4d5e6f7 The last commit where I fixed the file

• Change the word pick at the beginning of each line to edit.

  edit 75eedea First commit with the big file
  edit b2c3d4e Second commit, more changes
  edit c3d4e5f ...
  edit 3c4d5e6 ...
  edit 4d5e6f7 The last commit where I fixed the file

• Save the file and close the editor.

start editing in rebase

• Git will now drop you back at your very first commit in the list.

Now your current file system should have changed to contain all the old git committed project files at that point.

• (note: it includes the .gitignored files you have, just normal git behavior)

  • To remove that large file:

  # Replace with the actual path to your file
  git rm --cached path/to/your/large_file.ext

Then commit the change:

  git commit --amend --no-edit

Then continue the rebase to go to next commit point:

  git rebase --continue

• example cli:
  

  nsht@Azih MINGW64 /d/usp/uhpsj/study/build_llm_wsp/build_llm/src/build_llm_learn/p7_digitalsreeni_210_unet_segmentation_models (main|REBASE 2/13)
  $ git rebase --continue
  Stopped at 128ca80...  ^
  You can amend the commit now, with
  
    git commit --amend
  
  Once you are satisfied with your changes, run
  
    git rebase --continue
  
  nsht@Azih MINGW64 /d/usp/uhpsj/study/build_llm_wsp/build_llm/src/build_llm_learn/p7_digitalsreeni_210_unet_segmentation_models (main|REBASE 3/13)
  $ 
  

  • using Vscode Ide to change the file instead

• in your file system or vscode ide,
  
  open that file, edit it, save it.

• in the vscode git panel.
  
  stage the change. click commit.
  
  (just like how you normally commit a file in vscode.)

• click continue (continue rebase).

continue editing in rebase

• after git rebase --continue you are now at the next commit. just repeat the above process.

dealing with merge problem

• At some point you will face a merge problem when you modified the file

  CONFLICT (content): Merge conflict in src/build_llm_learn/p7_digitalsreeni_210_unet_segmentation_models/model_exec.ipynb

• example cli:
  

  nsht@Azih MINGW64 /d/usp/uhpsj/study/build_llm_wsp/build_llm/src/build_llm_learn/p7_digitalsreeni_210_unet_segmentation_models (main|REBASE 9/13)
  $ git rebase --continue
  Stopped at b9b9224...  @minor @ready for train
  You can amend the commit now, with
  
    git commit --amend
  
  Once you are satisfied with your changes, run
  
    git rebase --continue
  
  nsht@Azih MINGW64 /d/usp/uhpsj/study/build_llm_wsp/build_llm/src/build_llm_learn/p7_digitalsreeni_210_unet_segmentation_models (main|REBASE 10/13)
  $ git commit --amend --no-edit
  [detached HEAD 42118d6] @minor @ready for train
    Date: Fri Sep 19 20:04:50 2025 +0800
    6 files changed, 671 insertions(+), 3741 deletions(-)
    create mode 100644 src/build_llm_learn/p7_digitalsreeni_210_unet_segmentation_models/model_examine/examine_smp.ipynb
  
  nsht@Azih MINGW64 /d/usp/uhpsj/study/build_llm_wsp/build_llm/src/build_llm_learn/p7_digitalsreeni_210_unet_segmentation_models (main|REBASE 10/13)
  $ git rebase --continue
  Auto-merging src/build_llm_learn/p7_digitalsreeni_210_unet_segmentation_models/model_exec.ipynb
  CONFLICT (content): Merge conflict in src/build_llm_learn/p7_digitalsreeni_210_unet_segmentation_models/model_exec.ipynb
  error: could not apply f8b9733... ^ @working weak
  hint: Resolve all conflicts manually, mark them as resolved with
  hint: "git add/rm <conflicted_files>", then run "git rebase --continue".
  hint: You can instead skip this commit: run "git rebase --skip".
  hint: To abort and get back to the state before "git rebase", run "git rebase --abort".
  hint: Disable this message with "git config advice.mergeConflict false"
  Could not apply f8b9733... ^ @working weak
  
  nsht@Azih MINGW64 /d/usp/uhpsj/study/build_llm_wsp/build_llm/src/build_llm_learn/p7_digitalsreeni_210_unet_segmentation_models (main|REBASE 11/13)
  $
  

  • You can choose to just click on the vscode git panel to deal with the merge, (just like how you deal with a branch merge everyday. )

• Or, vscode git diff cant open the file, cuz it is too large.

  • I chose to blindly accept the old file at that point of commit. so:

  git checkout f8b9733 -- src/build_llm_learn/p7_digitalsreeni_210_unet_segmentation_models/model_exec.ipynb

but then unstage the file at vscode git panel.

and then open the file and manully change the file content.

then stage it again, commit it, continue rebase.

• note:

  • i mean, you can always just blindly accept a merge from any side. and then unstage it. and then overwrite the file completely with your desire content.
    • Here I did discard the modified file from the previous rebase edit. As long as I know what the final file should look like. Then it doesnt matter.

misc

answer with help from AI, tested.

• Here is my first AI prompt:

  1. 
  its a remote lib 
  1. 
  i clone it 
  1.
  i modify and commit things locally
  1.
  after 10 local commits
  1. 
  i found one of the existing file was 100mb and i was editing and committing on it 
  1.
  i change the code of that file, now its just 1mb.
  1.
  I now want to go back to the point where i first clone the repo
  and find that file 
  remove that file from my local commit 

  and go to next commit , remove that large file , or some other large files 
  and go to next commit , remove that large file , or some other large files 
  and go to next commit , remove that large file , or some other large files 
  and until the lasted commit where i refactor that file to 1mb. 
  and keep just that 1mb file. 

• PS: again, the markdown syntax i use is github style, it is incompatible with dev.to style. especially for the nested list. so the article structure will be unreadable.