Git 在执行 rebase 操作时，有时候会需要把当前分支中的若干次提交合并在一起，作为一次提交合并到主分支当中，这时候就要用到 squash 。顾名思义，squash 的用途是合并多次提交。
流程
初始状态
初始状态
开始 Rebase
在 Rebase 操作的同时进行 Squash。
开始 Rebase
完成 Rebase
完成 Rebase
操作
如图一所示，要合并 C5 、 C6 和 C7 三次提交，先切换到 C5 、 C6 和 C7 所在的分支，然后执行
git rebase -i HEAD~3
之后会出现如下提示信息
pick 708fa0a commit message A
pick 8baaa26 commit message B
pick dba177a commit message C
# Rebase 2d2fb07..bfa62a9 onto 2d2fb07 (3 command(s))
#
# 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
# d, drop = remove commit
#
# 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
这个时候把它改成如下形式
pick 708fa0a commit message A
squash 8baaa26 commit message B
squash dba177a commit message C
# ...
之后保存退出，出现
# This is a combination of 3 commits.
# The first commit's message is:
commit message A
# This is the 2nd commit message:
commit message B
# This is the 3rd commit message:
commit message C
再保存，就会显示合并成功的提示信息。
[detached HEAD bfa62a9] commit message A
Date: Fri Jun 17 16:32:31 2016 +0800
2 files changed, 3 insertions(+)
Successfully rebased and updated refs/heads/dev.
这时候，Rebase 合并成功，并且 C5 、 C6 和 C7 三次提交也合并在一起了。
补充
对于合并提示信息
pick 708fa0a commit message A
squash 8baaa26 commit message B
squash dba177a commit message C
squash 也可以改为 fixup
pick 708fa0a commit message A
squash 8baaa26 commit message B
fixup dba177a commit message C
它们二者的区别就在于 fixup 后面的提交信息会被忽略。
最后，合并提示信息也可以简写成这样
p 708fa0a commit message A
s 8baaa26 commit message B
f dba177a commit message C
