A .gitignore file tells Git which files or folders to ignore in a project. It's usually placed in the root directory of a repository.

Common uses:

• Ignore build output directories (e.g., dist/, build/)
• Skip dependency directories (e.g., node_modules/, vendor/)
• Exclude environment files with secrets (e.g., .env)
• Ignore OS-specific files (e.g., .DS_Store on macOS)
• Skip IDE and editor files (e.g., .vscode/, .idea/)

Basic rules:

• file.txt - Ignores exact filename
• *.txt - Ignores all .txt files
• build/ - Ignores build directory and its contents
• **/logs - Ignores logs directories in any location
• !important.txt - Never ignore important.txt