This is something I’m trying to remember, and it’s something that’s been answered before here.

I’ve beginning to experiment with HHVM as an alternative to using PHP, so I figured this would be useful to try out. Switching out the language that’s called when using PHP on the terminal is as simple as using this command:

sudo /usr/bin/update-alternatives --install /usr/bin/php php /usr/bin/hhvm 60

This will do it without any input, and you should be able to check by running. php -v. If you get hhvm version stuff, you should be good.

My next important question was how to switch back to using PHP. Again, simple:

sudo /usr/bin/update-alternatives --config php

It will then ask you to select from a list of options. My options were:

There are 2 choices for the alternative php (providing /usr/bin/php).

  Selection    Path            Priority   Status
------------------------------------------------------------
  0            /usr/bin/hhvm    60        auto mode
  1            /usr/bin/hhvm    60        manual mode
* 2            /usr/bin/php5    50        manual mode

Press enter to keep the current choice[*], or type selection number: