What is the difference between git am and git appl

问题:

Both git am and git apply can be used to apply patches. I fail to see the difference. I see a difference now: git am automatically commits whereas git apply only touches the files but doesn't create a commit. Is that the only difference?

回答1:

Both the input and output are different:

• git apply takes a patch (e.g. the output of git diff) and applies it to the working directory (or index, if --index or --cached is used).
• git am takes a mailbox of commits formatted as an email messages (e.g. the output of git format-patch) and applies them to the current branch.

git am uses git apply behind the scenes, but does more work before (reading a Maildir or mbox, and parsing email messages) and after (creating commits).

回答2:

git apply is for applying straight diffs (e.g. from git diff) whereas git am is for applying patches and sequences of patches from emails, either mbox or Maildir format and is the "opposite" of git format-patch. git am tries to extract commit messages and author details from email messages which is why it can make commits.

回答3:

With git am you apply the patch so if you use git status you won't see any local changes.

git apply enables you to make the changes in the source files as if you were writing the code by yourself, consequently git status and git diff will output the changes made in the patch you have applied, then you can fix/add more changes and submit them together as one new patch.