Git - Github Tips #

Terminology #

• HEAD: your current local working branch
• origin: the address to your remote git, represent for remote repo
• Tracked file: the file git already had before, so when you edit it, git knows this file is modified (M files)
  
• Untracked (new file): the file recently add and git don’t know anything about it (U files)
  
• Remote-tracking branches: References (in the form of origin/branch-name) that point to the branches in a remote repository

Commit #

git add .
git commit -m "commit message"

These 2 commands above can combie into 1:

git commit -am "commit message"

Note: this only work with tracked files

Change previous commit message #

Commit amend #

git commit --amend -m "new message to replace the previous message"

Note: this amend can also simplify by amen :))))

Rebase reword #

git rebase -i HEAD~1

git push -f

Opps! Code on wrong branch #

Stash #

git stash
git checkout correct-branch
git stash pop

Note: git stash will only bring the changes on tracked files to store but don’t worry when checkout to other branch, the untracked files will move to there also

Opps! Commit into local main branch #

Reset #

Solution 1: Erase the current commit and go back to the earlier commit

git reset --hard HEAD~1

Solution 2: Bring the current commit to staged change and go back to the earlier commit

git reset --soft HEAD~1

Update the outdated feature branch #

Relocate branch: rebase #

before rebase

after rebase

git checkout master
git pull
git rebase master topic
git push -f

Note: topic branch will have code from F and G of main branch, but if it conflicts with topic branch, the solution will be the same here

Clean up messy commits #

Accumulate commits: rebase fixup #

If you have 3 messy commits per 4 commits on your feature branch

git rebase -i HEAD~4

Vim IDE appear and show 4 latest commits

1. Type i to change into insert mode
2. Change pick to f or fixup → means you accumulate this 3 commits

3. Out insert mode with ESC key
4. Type :wq to save
   

git push -f

before	after

Note: the present commit will have all changes from 3 previous commits

Delete all local branches except main branch #

git branch | grep -v "main" | xargs git branch -D

Explain:

• Get all branches (except for the main) via git branch | grep -v "main" command
• Select every branch with xargs command
• Delete branch with git branch -D

Clean up outdated references #

• It only removes remote-tracking branches that no longer exist on the remote
• All local branches you’ve created yourself won’t be affected

git fetch --prune

Refresh outdated local branch #

• If you pull but show some warnings or errors and git show a recommend that is need to type some rebase commands
• Just checkout to another branch, delete your local conflict branch and then checkout to this branch again to download a latest one in remote repo

git checkout dev
git branch -D feature-branch
git fetch
git checkout feature-branch

Ignore all modified and new files and pull the latest version #

# Discard local changes (tracked files)
git reset --hard

# Clean untracked files
git clean -fd

# Pull the latest
git pull

Note: If you’re unsure, stash your changes first so you can recover them later with git stash

Merge PR but get stuck in conflict #

Relocate branch: rebase #

git checkout main
git pull
checkout feature-branch
git rebase main feature-branch

Conflict appears in IDE
→ Resolve conflict and save file

git add .
git rebase --continue

Vim IDE appear to make you confirm change
→ :wq

git push -f

Remote origin #

Check remote origin #

git remote -v

Change remote origin #

git remote set-url origin <url>
# E.g
git remote set-url origin git://new.url.here

Remove remote origin #

git remote remove origin

Log pretty #

git log --graph --decorate --oneline

or

git log --graph --decorate

Config #

Show current global credential #

git config --global --list

Configure local repo’s credential #

when you want it’s different with the global one

git config user.name DangPham112000
git config user.email dangpham112000@gmail.com

Switch git user tool #

• Git-User-Switch

Connecting to GitHub using SSH keys (Ubuntu) #

Checking for existing SSH keys #

ls -al ~/.ssh

Check the existing of these files:

• id_rsa.pub
• id_ecdsa.pub
• id_ed25519.pub

Generating a new SSH key #

ssh-keygen -t ed25519 -C "dangpham112000@gmail.com"

You can skip all the prompted by Enter

Adding your SSH key to the ssh-agent #

1. Start the ssh-agent in the background

   $ eval "$(ssh-agent -s)"
   > Agent pid 59566
   

2. Add your SSH private key to the ssh-agent

   ssh-add ~/.ssh/id_ed25519
   

Adding a new SSH key to account #

1. Copy the SSH public key to your clipboard

   cat ~/.ssh/id_ed25519.pub
   

   Then select and copy the contents of the id_ed25519.pub file displayed in the terminal to your clipboard

2. In the upper-right corner of any page on GitHub, click your profile photo, then click Settings

3. In the “Access” section of the sidebar, click SSH and GPG keys

4. Click New SSH key or Add SSH key

5. In the “Title” field, add a descriptive label for the new key. For example, if you’re using a personal laptop, you might call this key “Personal laptop”

6. Select the type of key, either authentication or signing

7. In the “Key” field, paste your public key

8. Click Add SSH key

Testing your SSH connection #

ssh -T git@github.com

You may see a message like this: Hi DangPham112000! You've successfully authenticated, but GitHub does not provide shell access.