git advanced operate

Abstract

learn some advanced operate of git, make manage code easily

Referance

https://learngitbranching.js.org/

HEAD

this can jump to which commit, you can get the log of per commit log.

git log

git checkout HASH

# previous one of HEAD
git checkout HEAD^

# previous x of HEAD
git checkout ~n

revert &reset

revert is for remot

git revert BRANCH
git revert HEAD

reset is for local

git reset HEAD~1
git reset BRANCH^

cherry-pick

copy the select scope commit to current BRANCH(HEAD)

git cherry-pick HASH_1 HASH_2

git cherry-pick c1 c2

interactive rebase

you can choose rebase branch with ui

reabse default to current branch(HEAD)

git rebase -i HEAD~4

forced to change branch

git branch -f xxxx

develop demo

we need to branch

branch	description
master	develop branch
bugFix	bugFix branch

when we develop at master branch, bug we want to test or debug somethig.

we need checkout to bugFix branch to test something, when we test over we checkout to master.

# ------------------------ first times to fix bug --------------------------------

# first time, create and checkout to bugFix branch
git checkout -b bugFix

#do something on bugFix branch
....

# we want to update the fixthing to master
git checkout master 
git merge bugFix

# ------------------------ n times to fix bug --------------------------------

# second time to test some thing, we still nedd to checkout bugFix branch
#  if excute this command
git checkout bugFix
git merge master
# you will see something like this

"""
Auto-merging index.txt
CONFLICT (content): Merge conflict in index.txt
Automatic merge failed; fix conflicts and then commit the result.
""

# the right command like this

# siwtch to bugFix then merge the branch what you wanto test or debug
git checkout bugFix
# -f means forced to excute 
git branch -f master

# then you can test on debug branch
....

# when we test over 
git checkout master 
git merge bugFix

what difference between HEAD~ and HEAD^

https://stackoverflow.com/questions/2221658/whats-the-difference-between-head-and-head-in-git

HEAD~ is
- Use most of the time — to go back a number of generations, usually what you want~ - Use on merge commits — because they have two or more (immediate) parents ^

G   H   I   J
 \ /     \ /
  D   E   F
   \  |  / \
    \ | /   |
     \|/    |
      B     C
       \   /
        \ /
         A
A =      = A^0
B = A^   = A^1     = A~1
C = A^2
D = A^^  = A^1^1   = A~2
E = B^2  = A^^2
F = B^3  = A^^3
G = A^^^ = A^1^1^1 = A~3
H = D^2  = B^^2    = A^^^2  = A~2^2
I = F^   = B^3^    = A^^3^
J = F^2  = B^3^2   = A^^3^2