How to generate and apply patches with git? — First published in fullweb.io issue #33

how-to-git-patch-diff.md

How to generate and apply patches with git?

It sometimes happen you need change code on a machine from which you cannot push to the repo. You’re ready to copy/paste what diff outputs to your local working copy.

You think there must be a better way to proceed and you’re right. It’s a simple 2 steps process:

1. Generate the patch:

git diff > some-changes.patch

2. Apply the diff:

Then copy this patch to your local machine, and apply it to your local working copy with:

git apply /path/to/some-changes.patch

And that’s it! The changes are now in your working copy and ready to be staged/commit/pushed :)

If you run git diff it will show changes that were tracked previously. But newly added files are not shown in the diff. To create a patch, I did the following.

• git add -A # Add everything to the staging area.
• git diff --staged --patch > changes.patch # --staged shows all the changes including new files
• git reset # Reset to the old state

Now, I can apply the changes.

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Edit: I just checked git diff --staged --patch and git diff --staged by creating two new patch files, and comparing them with the diff command. I don't find any difference.

@ssi-anik Didn't think about untracked files—I always forget about them when thinking about git command, thanks!

I believe you can simplify your solution even more by using intent-to-add like this:

git add --intent-to-add --all
# or
git add -NA

I can export the code change to .patch file, but the change only include the main part, Now I change the submodule and want to export the code change in submodule to the same .patch file so that I can apply the patch file for all code changes on new project including the submodule part, are there some commands to do this?

Hi

Git format-patch- 1- head

@MayuriVidekar, same error here on Windows. I'm pretty sure it used to work. Resorting now to git checkout -p the stash rev.

@MayuriVidekar @JulienCochuyt surely you're using PowerShell < 7.4. Upgrade or see https://stackoverflow.com/a/70283963/14098985 for workarounds.