Understanding the .gitignore File

Build artifacts, logs, secrets, and dependency folders should never be committed. The .gitignore file tells Git exactly which files to skip.

A .gitignore is just a text file full of patterns. Any path that matches a pattern is kept out of staging and commits, keeping your repo clean.

Drop a .gitignore at your repo root, one pattern per line. The example below ignores dependencies, logs, and your env file.

The basic patterns: *.log matches by extension, build/ matches a whole directory, and a plain name matches one exact file.

A leading slash anchors a pattern to the repo root, so /todo.txt ignores only the top-level file — not one with the same name deeper in the tree.

Prefix a pattern with ! to un-ignore something an earlier rule excluded — like ignoring all logs except one you want to keep.

For wildcards: a single * matches anything but a slash, while ** matches across directories at any depth.

Lines starting with # are comments and blank lines are skipped — use both to keep your .gitignore organized and readable.

Big gotcha: .gitignore only affects untracked files. If a file is already tracked, the rule does nothing until you untrack it with git rm --cached.

Not sure why a path is ignored? git check-ignore -v tells you exactly which rule and line matched it.

For personal clutter (editor configs, OS junk) that should never hit any repo, set a global ignore instead of polluting project files.

Test your .gitignore knowledge.

You mastered .gitignore: patterns, wildcards (*, **), anchoring (/), and negation (!). Remember it only touches untracked files — debug with git check-ignore.