I need to install on a lamp server exactly the same php extensions that are installed on an old server, how do to know exactly which extensions are installed in order to install the same on the new server?

3 Answers 3


You can use the command line switch -m to php to see what modules are installed.

$ php -m | head
[PHP Modules]

You could also use php -i to get phpinfo(); output via the command line which would include this info as well.


  • 5
    It should be noted, this may not be the same set of modules included by PHP running in Apache.
    – Rich Remer
    Nov 14, 2014 at 20:18

If the extension is actually being used, it will need to be referenced in php.ini somewhere. Extensions are loaded in a pretty intuitive manner:


etc, etc.

One thing to watch out for are extensions that are brought in by an additional ini file being included. I'm not sure about Debian, but on RHEL there's a /etc/php.d/ directory where all .ini files are treated like as if they had been in the main /etc/php.ini

If it's not in one of those two places (main php.ini or one of the included files) then the extension is more or less just sitting on the filesystem not being used.


Actually, I think I lied. You may have to look at your php files for calls to dl(). I don't know of many people who load extensions like that, though. Not even sure what the use case would be but it's another area you should probably check.

  • It's been a while since I built PHP, but I think you can also choose to have extensions compiled in statically, at which point neither of these options will help.
    – Jules
    Nov 14, 2014 at 20:20

In Debian, PHP extensions are loaded via files in /etc/php5/conf.d

There are two types of PHP Debian packages that might be installed here:

  • Debian PHP packages (which have names starting with php5- )
  • PECL PHP packages (which have names starting with php- )

To list both on your system, you can use this command: dpkg -l | grep 'ii php5\?-' which lists installed packages starting with either php- or php5- .

You also might have extensions that were built with PECL from source code. List those with: pecl list

Finally, it's possible to compile your own extensions the old fashioned way. In that case they might not have a file in /etc/php5/conf.d but might be added to php.ini itself.

All extensions usually have a section of output from phpinfo();. php -m will show the list of what extensions PHP has loaded (each of which should have a spot in the phpinfo output). There will be many more extensions listed in the php -m output than are installed as add-on packages in Debian, because there are lots of default extensions built into PHP as well as the ones you can install afterwards.

Here is example output from a development machine listing extra installed PHP extensions:

root@zaphod:~# dpkg -l | grep 'ii  php5\?-'
ii  php-auth-sasl                         1.0.4-1                            all          Abstraction of various SASL mechanism responses
ii  php-db                                1.7.14-2                           all          PHP PEAR Database Abstraction Layer
ii  php-mail                              1.2.0-4                            all          PHP PEAR module for sending email
ii  php-mail-mime                         1.8.4-1                            all          PHP PEAR module for creating MIME messages
ii  php-mail-mimedecode                   1.5.5-1                            all          PHP PEAR module to decode MIME messages
ii  php-net-smtp                          1.6.1-1                            all          PHP PEAR module implementing SMTP protocol
ii  php-net-socket                        1.0.9-2                            all          PHP PEAR Network Socket Interface module
ii  php-pear                              5.4.39-0+deb7u2                    all          PEAR - PHP Extension and Application Repository
ii  php-xml-parser                        1.3.4-6                            all          PHP PEAR module for parsing XML
ii  php5-cgi                              5.4.39-0+deb7u2                    amd64        server-side, HTML-embedded scripting language (CGI binary)
ii  php5-cli                              5.4.39-0+deb7u2                    amd64        command-line interpreter for the php5 scripting language
ii  php5-common                           5.4.39-0+deb7u2                    amd64        Common files for packages built from the php5 source
ii  php5-curl                             5.4.39-0+deb7u2                    amd64        CURL module for php5
ii  php5-dev                              5.4.39-0+deb7u2                    amd64        Files for PHP5 module development
ii  php5-gd                               5.4.39-0+deb7u2                    amd64        GD module for php5
ii  php5-imagick                          3.1.0~rc1-1+b2                     amd64        ImageMagick module for php5
ii  php5-imap                             5.4.39-0+deb7u2                    amd64        IMAP module for php5
ii  php5-intl                             5.4.39-0+deb7u2                    amd64        internationalisation module for php5
ii  php5-mcrypt                           5.4.39-0+deb7u2                    amd64        MCrypt module for php5
ii  php5-mysql                            5.4.39-0+deb7u2                    amd64        MySQL module for php5
ii  php5-pgsql                            5.4.39-0+deb7u2                    amd64        PostgreSQL module for php5
ii  php5-sqlite                           5.4.39-0+deb7u2                    amd64        SQLite module for php5
ii  php5-suhosin-extension                0.9.37-2                           amd64        advanced protection system for PHP5
ii  php5-sybase                           5.4.39-0+deb7u2                    amd64        Sybase / MS SQL Server module for php5
ii  php5-xdebug                           2.2.1-2                            amd64        Xdebug Module for PHP 5
root@zaphod:~# pecl list
Installed packages, channel pecl.php.net:
Package  Version State
APC      3.1.13  beta
memcache 3.0.8   beta

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