TIL: Get file list from eslint, biome and ruff

Seeing which files are being processed by linter tools is surprisingly difficult. A common use case is when you’re trying to debug why your linter is taking ages, and you discover it’s trying to lint bundled JS files.

Here are the shortest commands I could come up with for eslint and biome:

eslint

eslint --debug 2>&1 | grep /repo | sed 's|.*/repo||' | sort -u

biome

biome check --colors=off --log-level=info --log-kind=pretty . | grep 'path' | sed 's|.*\./||' | sort -u

update: biome recently added file listing to the verbose flag, so it can be simplified to:

biome check --verbose

For Python, ruff supports a flag (–show-files), but only for “check”, not for the “format” command:

ruff

ruff check --fix --show-files . // works
ruff format --show-files . // doesn’t work

Why do these tools make it so difficult to see this information? Prettier shows it by default on every run - not even a flag is needed.