Дистрибутив и список установленных пакетов в студию.
Узнать дистриб можно из консоли:
cat /etc/os-release
список пакетов:
sudo dpkg --list | grep php
Пример вывода у меня:
alex@SUNDUKOV:~$ cat /etc/os-release
NAME="Ubuntu"
VERSION="12.04.5 LTS, Precise Pangolin"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu precise (12.04.5 LTS)"
VERSION_ID="12.04"
alex@SUNDUKOV:~$ sudo dpkg --list | grep php
ii dh-php 0.23+deb.sury.org~precise+1 debhelper add-on to handle PHP PECL extensions
ii dh-php5 0.2+deb.sury.org~precise+1 debhelper add-on to handle PHP PECL extensions
ii php-common 1:45+deb.sury.org~precise+1 Common files for PHP packages
ii php-gearman 2.0.2+1.1.2-1+deb.sury.org~precise+1 PHP wrapper to libgearman
ii php-pear 1:1.10.1+submodules+notgz-8+donate.sury.org~precise+2 PEAR Base System
ii php-xdebug 2.5.0-1+deb.sury.org~precise+1 Xdebug Module for PHP
ii php-xml 1:7.0+45+deb.sury.org~precise+1 DOM, SimpleXML, WDDX, XML, and XSL module for PHP [default]
ii php5-cli 5.5.37+dfsg-1+deprecated+dontuse+deb.sury.org~precise+1 command-line interpreter for the php5 scripting language
ii php5-common 5.5.37+dfsg-1+deprecated+dontuse+deb.sury.org~precise+1 Common files for packages built from the php5 source
ii php5-curl 5.5.37+dfsg-1+deprecated+dontuse+deb.sury.org~precise+1 CURL module for php5
ii php5-dev 5.5.37+dfsg-1+deprecated+dontuse+deb.sury.org~precise+1 Files for PHP5 module development
ii php5-fpm 5.5.37+dfsg-1+deprecated+dontuse+deb.sury.org~precise+1 server-side, HTML-embedded scripting language (FPM-CGI binary)
ii php5-json 1.3.9-1+deb.sury.org~precise+3 JSON module for php5
ii php5-memcache 3.0.8-5+deb.sury.org~precise+1 memcache extension module for PHP5
ii php5-memcached 2.2.0-2+deb.sury.org~precise+1 memcached extension module for PHP5, uses libmemcached
ii php5-mysql 5.5.37+dfsg-1+deprecated+dontuse+deb.sury.org~precise+1 MySQL module for php5
ii php5-readline 5.5.37+dfsg-1+deprecated+dontuse+deb.sury.org~precise+1 Readline module for php5
ii php5-redis 2.2.7-1+deb.sury.org~precise+1 PHP extension for interfacing with Redis
ii php5-xdebug 2.3.2-1+deb.sury.org~precise+1 Xdebug Module for PHP 5
ii php5.5 5.5.38-4+deb.sury.org~precise+1 server-side, HTML-embedded scripting language (metapackage)
ii php5.5-cli 5.5.38-4+deb.sury.org~precise+1 command-line interpreter for the PHP scripting language
ii php5.5-common 5.5.38-4+deb.sury.org~precise+1 documentation, examples and common module for PHP
ii php5.5-dev 5.5.38-4+deb.sury.org~precise+1 Files for PHP5.5 module development
ii php5.5-fpm 5.5.38-4+deb.sury.org~precise+1 server-side, HTML-embedded scripting language (FPM-CGI binary)
ii php5.5-json 5.5.38-4+deb.sury.org~precise+1 JSON module for PHP
ii php5.5-mbstring 5.5.38-4+deb.sury.org~precise+1 MBSTRING module for PHP
ii php5.5-mysql 5.5.38-4+deb.sury.org~precise+1 MySQL module for PHP
ii php5.5-opcache 5.5.38-4+deb.sury.org~precise+1 Zend OpCache module for PHP
ii php5.5-readline 5.5.38-4+deb.sury.org~precise+1 readline module for PHP
ii php7.0-cli 7.0.13-1+deb.sury.org~precise+1 command-line interpreter for the PHP scripting language
ii php7.0-common 7.0.13-1+deb.sury.org~precise+1 documentation, examples and common module for PHP
ii php7.0-curl 7.0.13-1+deb.sury.org~precise+1 CURL module for PHP
ii php7.0-dev 7.0.13-1+deb.sury.org~precise+1 Files for PHP7.0 module development
ii php7.0-fpm 7.0.13-1+deb.sury.org~precise+1 server-side, HTML-embedded scripting language (FPM-CGI binary)
ii php7.0-intl 7.0.13-1+deb.sury.org~precise+1 Internationalisation module for PHP
ii php7.0-json 7.0.13-1+deb.sury.org~precise+1 JSON module for PHP
ii php7.0-mbstring 7.0.13-1+deb.sury.org~precise+1 MBSTRING module for PHP
ii php7.0-mcrypt 7.0.13-1+deb.sury.org~precise+1 libmcrypt module for PHP
ii php7.0-mysql 7.0.13-1+deb.sury.org~precise+1 MySQL module for PHP
ii php7.0-opcache 7.0.13-1+deb.sury.org~precise+1 Zend OpCache module for PHP
ii php7.0-pgsql 7.0.13-1+deb.sury.org~precise+1 PostgreSQL module for PHP
ii php7.0-readline 7.0.13-1+deb.sury.org~precise+1 readline module for PHP
ii php7.0-xml 7.0.13-1+deb.sury.org~precise+1 DOM, SimpleXML, WDDX, XML, and XSL module for PHP
ii pkg-php-tools 1.21+deb.sury.org~precise+1 various packaging tools and scripts for PHP packages
соотвественно под версию 7 я ставил так:
#apt-get install php7.0-mbstring 
