Use Stream.finished. $ node -e "const { Stream } = require('stream'); s = process.stdout; s.write('@'.repeat(128 * 1024)); Stream.finished(s, () => { proce

Use Stream.finished. $ node -e "const { Stream } = require('stream'); s = process.stdout; s.write('@'.repeat(128 * 1024)); Stream.finished(s, () => { process.exit(0); })" | wc -c 131072 https://nodejs.org/api/stream.html#streamfinishedstream-options-callback https://nodejs.org/api/stream.html#streamfinishedstream-opti...