Amending

Amending

git amend allows the last commit to be fixed

This is very useful to rewrite commits that were done too soon

Greatly helps with keeping a clean history

Amending

git commit --amend:

   → adds all newly staged items into the latest commit

   → calls the editor to write the new commit message

For short, you can use:

git commit --amend -m "MESSAGE"

Branches and Merging

Branches

git allows development to take place in multiple branches

Branches allow different teams to work on different tasks in parallel - alternate realities

Branches also allow for quickly dumping out bad ideas

Branches

Branches

Working on the main branch is not a great idea

You can create branches with:
git branch BRANCH_NAME

Move to a new branch with:
git checkout BRANCH_NAME or git switch BRANCH_NAME

Merging

You can merge the changes from one branch into another:

   → First, checkout or switch to the branch that should receive the changes

   → Second, merge all changes with the command: git merge BRANCH_NAME

   → Third, delete obsolete branches with: git branch -d BRANCH_NAME

Remember

You merge the contents of one branch into another

I.e., you need to first move to the branch that will receive the changes

Than, you merge the branch that contain the changes

Conflicts

Two different branches changing the same lines of code: CONFLICT

Git will let you know when conflicts happen

You can review all conflicts prior to commiting a merge

Reseting

reset

Hard reset

git reset --hard

Sets working directory and staging area back to latest commit

Very dangerous command!

For a specific file: git restore FILENAME

Mixed reset

git reset or git reset --mixed

Unstage changes; does not change working directory

For a specific file: git reset FILENAME

Soft reset

git reset --soft

Simply updates the HEAD pointer

No change to the working directory or staging area

Normally used to combine commits:
git reset --soft HEAD~3

revert

git revert is a safe way of undoing things

It adds a new commit, undoing the changes of a previous commit

Examples: git revert 32a2d or git revert HEAD~2

Rebasing

Rebase

Rebasing can be used to achieve two different goals:

→ Maintain a linear project history

→ Rewriting past history

It is normally a bad idea to rebase public history!

Linear History

Merging can make a project history harder to follow

Rebase can be used to keep a linear history using the commands:

git checkout branch_name

git rebase main

See Introduction Sequence #4 from this link

Rebase

Remember

You rebase the base (starting point) of a given branch

I.e., you need to first move to the branch that will be rebase

Than, you provide its new base (starting point)

Rewriting Past History

Rebasing can be done interactively to rewrite past history:

git rebase -i STARTING_POINT

You can invert the order of commit, squash commits together, rewrite comments, etc.