The Pecl command can be used to install PHP extensions, which can solve the problem in minutes. Previously, PHP extensions were installed by downloading source code and compiling and installing them. In the end, I was confused. I searched online and found that I could use the Pecl command to install it. It is so convenient! Here is how to install PHP extensions using the Pecl command. PECL is a repository for PHP extensions, which provides a directory of all known extensions and hosting facilities for downloading and developing PHP extensions.