Adopt the following code https://github.com/ikappas/vscode-phpcs/blob/5ec0314d0187f8cedd004a453b6859ff948664bd/phpcs-server/src/linter.ts#L187-L206 Since stderr is always an error, we can switch to STREAM_BOTH mode (which is the default) and will get some automatic handling for SL >4.3 Parsing fatal errors within stdin, is marked 'needs help'