To install PHP on a Linux system, you will need to follow these steps:
Install the necessary dependencies for PHP. This may include libraries such as libxml, libcurl, and others. You can use the package manager of your Linux distribution to install these dependencies.
Download the PHP source code from the PHP website (https://www.php.net/) or from a mirror.
Extract the PHP source code to a directory on your system.
Change to the directory containing the extracted PHP source code.
Run the ./configure script to configure the PHP build. You can pass options to the configure script to specify the features and modules that you want to include in the build.
Run the make command to build PHP.
Run the make install command to install PHP.
To upgrade PHP on a Linux system, you will need to follow similar steps. However, you will need to download and install the newer version of PHP, rather than the initial installation.
It's important to note that the exact steps for installing or upgrading PHP on a Linux system may vary depending on your Linux distribution and the version of PHP that you are installing or upgrading to. Consult the PHP documentation and your system's documentation for more information.