Managing multiple versions of PHP on Mac OS X with Homebrew

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October 12, 2016

I sense a trend starting.

A few weeks ago, I wrote a post about managing different versions of Python on Mac OS X, and today I’m going to explain how I use multiple versions of PHP on the same platform.

The Problem

Until the homebrew-php group figure out a better way of handling several versions of PHP (their instructions haven’t worked for several months), and without installing something like phpenv, I concocted my own means to manage PHP versions using bash aliases similar to my Python post.

(Command line output that I’ve pasted below may be truncated for brevity.)

Step 1: Install your favorite versions of PHP

Homebrew is still awesome at installing PHP, but trying to install multiple versions back-to-back will produce errors:

$ brew tap homebrew/dupes
$ brew tap homebrew/versions
$ brew tap homebrew/homebrew-php
$ brew install php{5{5,6},7{0,1}}
Error: Cannot install homebrew/php/php56 because conflicting
formulae are installed.
  php55: because different php versions install the same binaries.
Please `brew unlink php55` before continuing.

There’s an easy way around it:

$ for i in 55 56 70 71; do 
> brew install php$i
> brew unlink php$i
> done

This will install PHP 5.5, 5.6, 7.0 and 7.1, unlinking each version right after its installation, and leaving you with PHP 7.1 as your system default.

Step 2: Bash aliases

I put all of my aliases in a file in my home directory and call that from within my .bashrc file. (your system may use .bash_profile which will operate in the same way.

# ~/.bashrc
# put this at the bottom of the file
if [ -f ~/ ]; then
    . ~/
# ~/
function unlink_php {
  for i in `ls -1 /usr/local/opt/ | grep php | cut -c4-5 | uniq`; do
    brew unlink php$i > /dev/null
for i in `ls -1 /usr/local/opt/ | grep php | cut -c4-5 | uniq`; do
  alias php$i="unlink_php && brew link php$i"

The unlink_php function basically auto-detects which versions of PHP you have installed with homebrew, and unlinks all of them. I’m sure you could be clever and detect via php -version which version is currently linked and just unlink that one, but this gives me peace of mind that ALL versions are properly unlinked.

Then, it uses the same auto-detection to create aliases for each version which also calls the unlink_php function so any time I switch to a different PHP version, Homebrew will unlink all others and re-link the version I want.

Now you can source that aliases script and you should be in business:

$ source ~/

Step 3: Magic

Verify that your new aliases are made:

$ alias | grep php
alias php55='unlink_php && brew link php55'
alias php56='unlink_php && brew link php56'
alias php71='unlink_php && brew link php71'

And then you can switch your version of PHP using your alias:

$ php55
Linking /usr/local/Cellar/php55/5.5.38_11... 17 symlinks created
$ php --version
PHP 5.5.38
$ php71
Linking /usr/local/Cellar/php71/7.1.0-rc.3_8... 17 symlinks created
$ php --version
PHP 7.1.0RC3