Is it possible to get a list of installed php extensions on Debian? Is there any simple way to find which extensions exist in debian php packages and which have to be compiled manually (actually three lists would be useful: all enabled extensions, all installed extensions, enabled and not enabled, all extensions available as deb packages for a given debian version)?
Not entirely sure about what you're trying to accomplish, but it seems like this will do the trick:
dpkg -l | grep php
To search for PHP packages that are available in
apt, you can do something like this:
apt-cache search php | grep '^php'
Invoking the following will give you a list of modules that are currently loaded in the PHP runtime (including built-in modules), but it will be limited to the CLI version, not the webserver module for PHP per se:
phpinfo() from a PHP script will give you more extensive information.