Git系列3：Git查看历史提交信息

• 单行日志：
  git-log --oneline -2
• 图形记录
  $ git log --oneline --graph --all

• 91ee5aa (HEAD -> master) Merge branch 'branch1'
  |
  | * ec70678 (branch1) branch1 modify
• | 88a0812 (origin/master) switch to master
• | d8d9cb0 Commit log
• | 1ecdbdd (tag: add) init commit\r\n 1) by bruce
  |/
• 98b5721 Nothing
• 3f289ec Add filea.txt

• 显示指定git id的提交信息

$ git show 3f28
commit 3f289ececf67f669d74e79b4222a5bfc5d04154d
Author: Bruce Zhang 
Date:   Mon Dec 23 15:21:43 2019 +0800

    Add filea.txt

diff --git a/filea.txt b/filea.txt
new file mode 100644
index 0000000..e69de29

• 计算文件内容SHA-1: git hash-object

• Git references: HEAD
  git show HEAD

• 当前状态
  git status

• git log --oneline --graph
  -git show
  git show HEAD~ #same as HEAD~1 means parent.
  git show HEAD~2 #parent's parent

• TAG
  git tag
  git show
  git tag []
  git tag xxx HEAD^ # tag the previous commit