🔍 Ctrl+K
🟢 Easy

Git & GitHub

Git: version control — track changes, go back, collaborate, branches for testing without affecting main.

GitHub: hosting platform — stores code online, collaborates.

Bash 
git init
git add .
git commit -m 'message'
git push -u origin main
git clone <url>
git status
git log
git branch / git branch <name>
git checkout <branch> / git checkout -b <new>
git pull origin develop
git stash
git revert <commit>
Merge Conflicts
2 devs edit same line (df.filter status) → git pull origin develop before push, resolve manually. Merge conflicts: GitHub cannot decide which version to keep. Resolve conflicts manually in editor (choose correct logic), stage and commit again. Avoid with small frequent commits and PRs.

Large files: GitHub rejects files > 100MB — do not commit large data files.

Accidental push to main: bypasses code review and may break production. Solution: branch protection rules — require PR before merge, block direct push to main.

Secrets pushed accidentally: credentials can be exploited. Never hardcode; store in AWS Secrets Manager. If pushed, rotate immediately.

More commands from doc: git rm removes files, git reset undo commits / unstage files, git pull downloads updates, git add <file> stages specific files.

Credentials stored in AWS Secrets Manager (all connection details).

🟢 Easy

Secrets Manager

All connection and credential details in AWS stored in AWS Secrets Manager, not hardcoded.

🟢 Easy

Status Codes

From file: 1xx informational, 2xx success, 3xx redirection, 4xx client error, 5xx server error

Python 
status_codes = {100:"Informational",200:"Success",300:"Redirection",400:"Client Error",500:"Server Error"}
for code, desc in status_codes.items():
    print(f"{code}: {desc}")