Ignoring Log Files in Git Repositories

Log files are generated at runtime and should never be version-controlled. They contain timestamps, machine-specific paths, and transient state that changes with every execution. Committing them pollutes your git history with meaningless noise.

Common log patterns to ignore:

*.log
logs/
npm-debug.log*
yarn-debug.log*
yarn-error.log*
pnpm-debug.log*
lerna-debug.log*

Package manager debug logs:

• npm-debug.log — Created when npm install or npm run encounters an error. Contains the full npm execution trace with environment details.
• yarn-debug.log and yarn-error.log — Yarn's equivalent debug output.
• pnpm-debug.log — pnpm's diagnostic log.

These files often contain your file system paths, environment variables, and system information that you may not want in a public repository.

Application logs:

• *.log — The wildcard pattern catches most log files. Be cautious: if your project contains intentional .log files that are source material (rare but possible), use more specific patterns instead.
• logs/, log/ — Common directories where applications write rotating log files.
• *.log.gz, *.log.[0-9] — Rotated and compressed log archives from tools like logrotate or winston.

Runtime and crash logs:

• hs_err_pid*.log — JVM HotSpot crash dumps containing stack traces and memory state.
• crash.log — Generic crash reports from various runtimes.
• *.pid — Process ID files written by daemons and servers.

Best practices for log management:

1. Configure your application to write logs to a dedicated logs/ directory and add that directory to .gitignore.
2. Use log aggregation services (Datadog, CloudWatch, ELK Stack) instead of relying on local log files for production debugging.
3. Never log secrets — sanitize environment variables and credentials from log output at the application level.
4. Git hooks — consider a pre-commit hook that warns if .log files are staged accidentally.

Edge case: If you need to commit an example log file for documentation or testing, use the negation pattern !example.log to override the wildcard rule.