The bin/webpack-dev-server command is not as smart as e.g. rails server, where it shows the proper fix within the error message.

$ bin/webpack-dev-server                                                                  
yarn run v1.19.1
error Command "webpack-dev-server" not found.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

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Rails LTS provides security patches for old versions of Ruby on Rails (2.3, 3.2, 4.2 and 5.2)

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Read more Show archive.org snapshot

Run yarn install --check-files to fix this error.