Gitignore File Configuration Guide: Keep Only What You Need in Your Repository

.gitignore is a core configuration file for Git repositories, used to specify files/folders that are not tracked, preventing repository bloat and sensitive information leaks. It is a text file in the root directory with one rule per line, and can be quickly generated using templates like gitignore.io. Core syntax includes: ignoring specific files/folders (e.g., temp.txt, logs/); using wildcards for batch ignoring (*.log, *.tmp); recursively ignoring subdirectories (**/temp.txt); negative rules (!debug.log); and comments (#). Common scenarios include ignoring node_modules/.env/dist/ in frontend projects, __pycache__/venv/ in Python projects, and system files like .DS_Store/Thumbs.db. If a file has already been tracked, it needs to be removed with `git rm --cached` before committing the .gitignore. Ensure accurate paths, distinguish between directories and files, rules take effect recursively, and avoid excluding the .gitignore file itself. Mastering .gitignore helps maintain a clean and efficient repository, enhancing collaboration experience.