curl

curl, at 26 years old, is the most installed open-source tool on Earth, with over 20 billion deployments across cars, TVs, and every operating system. Daniel Stenberg's command-line utility transfers data using over 200 protocols, handling trillions of HTTPS requests annually. It is faster than the average data transfer tool, completing file downloads with 15% less overhead than wget. Embedded in IoT devices and stock exchanges alike, curl proves that simplicity and ubiquity define true indispensability, supporting use cases from API testing to firmware updates.