What is the main purpose of hosts file?

The hosts file is a plain text file used by operating systems to map hostnames to IP addresses. Its primary purpose is to enable the resolution of domain names to their corresponding IP addresses locally, bypassing the need for DNS lookup. This can improve network efficiency, facilitate testing of websites before DNS changes propagate, or block specific websites by redirecting them to a different IP. It is commonly found in systems like Windows, macOS, and Linux.