Git修改/合并 提交历史

修改最后一次提交

场景：用户新增文件a，做了一次提交，提交消息为：“add file a”。
之后用户新增文件b。此时用户可以再次做一次提交，比如提交消息为“add file b”, 但这样做就有两条类似的消息，过于冗余可简化。
用户在第二次提交时执行 git commit --amend ，此刻能修改上次提交的消息，保存后两次提交会合并为一次提交。

合并提交

git rebase -i HEAD~3

运行这个命令会在文本编辑器上会看到一个 vim 界面

pick f7f3f6d changed my name a bit
pick 310154e updated README formatting and added blame
pick a5f4a0d added cat-file

# Rebase 710f0f8..a5f4a0d onto 710f0f8
#
# Commands:
#  p, pick = use commit
#  r, reword = use commit, but edit the commit message
#  e, edit = use commit, but stop for amending
#  s, squash = use commit, but meld into previous commit
#  f, fixup = like "squash", but discard this commit's log message
#  x, exec = run command (the rest of the line) using shell
#
# These lines can be re-ordered; they are executed from top to bottom.
# If you remove a line here THAT COMMIT WILL BE LOST.
# However, if you remove everything, the rebase will be aborted.
# Note that empty commits are commented out

如果指定 “squash” 而不是 “pick” 或 “edit”，Git 将应用两者的修改并合并提交信息在一起。如果想把这三次提交变为一个提交，可以这样修改：

# 记住不要动最上面的那行 vim修改后记得保存
pick f7f3f6d changed my name a bit
squash 310154e updated README formatting and added blame
squash a5f4a0d added cat-file

 :wq 保存并退出编辑器时，会显示另一个 vim 界面，Git 应用所有的三次修改放到编辑器中来合并三次提交信息：

# This is a combination of 3 commits.
# The first commit's message is:
changed my name a bit

# This is the 2nd commit message:

updated README formatting and added blame

# This is the 3rd commit message:

added cat-file

保存后就拥有了一个包含前三次提交的全部变更的提交。

最后使用 git log --oneline 确认所有这次开发中的 commit message 都被压缩成了一个。