How to use the php that brew installed?

According to the contributors of the Homebrew php formula...

The contributors of the Homebrew php formula give the following instructions. The exact instructions reproduced here install php7.4. Substitute the php version you need.

(Avoid "special" ways of accomplishing your objective; they are often problematic. "Official" approaches are more likely to give you a predictable, maintainable setup.)

$ brew search php // since php can be installed by homebrew but be missing from your PATH, review the list of php versions available through homebrew; a checkmark next to a version indicates one is installed
$ brew install php@7.4
$ echo 'export PATH="/usr/local/opt/php@7.4/bin:$PATH"' >> ~/.zshrc // add the alias to your path (issues you are using zsh, the default now for macOS); see comments output during installation
$ source ~/.zshrc // reload . zshrc to use the new settings immediately

The contributors of the formula also provide the following instructions for enabling PHP in Apache:

To enable PHP in Apache add the following to httpd.conf and restart Apache:

   LoadModule php_module /usr/local/opt/php/lib/httpd/modules/libphp.so  

   <FilesMatch \.php$>  
       SetHandler application/x-httpd-php  
   </FilesMatch>`

Finally, check DirectoryIndex includes index.php

   DirectoryIndex index.php index.html  

The php.ini and php-fpm.ini file can be found in:

   /usr/local/etc/php/7.4/

These instructions for enabling PHP in Apache appear in stdout when you install php. Alternatively in Terminal use brew info php or visit the Homebrew PHP formula page

brew install php installs php 7.3 at the moment, versions below are keg-only

You can make aliases for versions below by adding this to:

~/.profile

alias php@5.6='$(brew --prefix php@5.6)/bin/php'
alias php@7.0='$(brew --prefix php@7.0)/bin/php'
alias php@7.1='$(brew --prefix php@7.1)/bin/php'
alias php@7.2='$(brew --prefix php@7.2)/bin/php'

~/.bashrc

source ~/.profile

~/.zshrc

[[ -e ~/.profile ]] && emulate sh -c 'source ~/.profile'

Then you can:

php@5.6 -v
php@7.0 -v
php@7.1 -v
php@7.2 -v

If you use composer and the platform php is not set in your project then this can be handy:

~/.profile

alias composer@5.6='php@5.6 $(which composer)'
alias composer@7.0='php@7.0 $(which composer)'
alias composer@7.1='php@7.1 $(which composer)'
alias composer@7.2='php@7.2 $(which composer)'

If you use artisan a lot (artisan maps to php which is 7.3) then this can be handy:

~/.profile

alias artisan@5.6='php@5.6 artisan'
alias artisan@7.0='php@7.0 artisan'
alias artisan@7.1='php@7.1 artisan'
alias artisan@7.2='php@7.2 artisan'

I would create an alias to it so you don't disturb the system PHP install.

brew info php71

Brew installs into /usr/local/Cellar so you can add the following to your ~/.bash_alias or ~/.profile.

alias php7='/usr/local/Cellar/php71/7.1.10_21/bin/php'

Try: brew link php71 --force to use brew specific php version. It worked for me.

As of 2021, all you need is

brew install php

then

brew link php

This will give you php 8.0 and setup your symlinks.