How to select from a list of "or" - dependencies?

Question

Example: https://packages.ubuntu.com/bionic/php7.2

php package depends on one of:

• libapache2-mod-php7.2
• php7.2-fpm
• php7.2-cgi

Running sudo apt install php always installs the first of these dependencies, unless one of the others has been installed already. Even running sudo apt install php php-cli installs the first dependency.

How can I select e.g. php-cgi in one go ?

So instead of

sudo apt install php-cgi && sudo apt install php

I want something like

sudo apt install --select-dependency php-cgi php

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Please note that php is just an example, I'm looking for a general answer.

Answer 1

You can provide multiple arguments to apt install to dictate which packages you want to install in one go - this is so automated installation scripts and such as well as users can install all the defined packages in a single go rather than trying to do it one by one by one.

The general syntax is this:

sudo apt install package1 package2 package3 package4 ...

How the various packages behave with this will vary based on the package and its dependencies.

But in the case of php its its own hell to install because in SOME cases apt is stupid when resolving the dependencies, so if you need php-cli just install it and only it:

sudo apt install php-cli

Same behavior for php-fpm too or php-cgi - just install it, it'll pull in the common dependencies it needs.