Git update a specific commit

Current commits:

$ git log --oneline
50751d6 (HEAD -> master) Add file03
37dfeb1 Add file02
01f470d Add file01

Assume I need to update the commit 37dfeb1.

$ echo "Some changes to file02" >> file02

$ git status
On branch master
Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git checkout -- <file>..." to discard changes in working directory)

        modified:   file02

no changes added to commit (use "git add" and/or "git commit -a")

• Step 1: Stash the changes

$ git stash
warning: LF will be replaced by CRLF in file02.
The file will have its original line endings in your working directory.
Saved working directory and index state WIP on master: 50751d6 Add file03

$ git show stash
commit ebe8d7a79186a36d34e2e778a0f29e43e59879ed (refs/stash)
Merge: 50751d6 8bb2954
Author: xxx
Date:   xxx

    WIP on master: 50751d6 Add file03

diff --cc file02
index 9e22bcb,9e22bcb..ee96a91
--- a/file02
+++ b/file02
@@@ -1,1 -1,1 +1,2 @@@
  02

• Step 2: Rebase to the commit to be updated:

$ git rebase -i 37dfeb1

• Step 3: In the vim editor, change pick to edit
pick 507551d6 xxx -> edit 507551d6 xxx.
• Step 4: Take a look at the status:

$ git status
interactive rebase in progress; onto 37dfeb1
Last command done (1 command done):
   edit 50751d6 Add file03
No commands remaining.
You are currently editing a commit while rebasing branch 'master' on '37dfeb1'.
  (use "git commit --amend" to amend the current commit)
  (use "git rebase --continue" once you are satisfied with your changes)

• Step 5: Pop the stash

$ cat file02
02

$ git stash pop stash@{0}
interactive rebase in progress; onto 37dfeb1
Last command done (1 command done):
   edit 50751d6 Add file03
No commands remaining.
You are currently editing a commit while rebasing branch 'master' on '37dfeb1'.
  (use "git commit --amend" to amend the current commit)
  (use "git rebase --continue" once you are satisfied with your changes)

Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git checkout -- <file>..." to discard changes in working directory)

        modified:   file02

no changes added to commit (use "git add" and/or "git commit -a")
Dropped stash@{0} (ebe8d7a79186a36d34e2e778a0f29e43e59879ed)

$ cat file02
02
Some changes to file02

• Step 6: Save the changes

$ git add file02

$ git commit --amend --no-edit
[detached HEAD 2806b3e] Add file03
 Date: Thu May 23 17:27:08 2019 +0800
 2 files changed, 2 insertions(+)
 create mode 100644 file03

$ git status
interactive rebase in progress; onto 37dfeb1
Last command done (1 command done):
   edit 50751d6 Add file03
No commands remaining.
You are currently editing a commit while rebasing branch 'master' on '37dfeb1'.
  (use "git commit --amend" to amend the current commit)
  (use "git rebase --continue" once you are satisfied with your changes)

nothing to commit, working tree clean

• Step 7: Continue the rebase

$ git rebase --continue
Successfully rebased and updated refs/heads/master.

$ git status
On branch master
nothing to commit, working tree clean

$ git log --oneline
2806b3e (HEAD -> master) Add file03
37dfeb1 Add file02
01f470d Add file01

$ cat file02
02
Some changes to file02

Alternatively we can update the changes after git rebase -i 37dfeb1, without using git stash.

Bear in mind, after the updated commit, all further commits' SHA hash value will be changed.