在安装php的时候，不管是编译安装：
./configure --prefix=/usr/local/php --with-config-file-path=/usr/local/php/etc --with-mysql=/usr/local/mysql --with-mysqli=/usr/local/mysql/bin/mysql_config --with-iconv-dir --with-freetype-dir --with-jpeg-dir --with-png-dir --with-zlib --with-libxml-dir=/usr --enable-xml --disable-rpath --enable-discard-path --enable-magic-quotes --enable-safe-mode --enable-bcmath --enable-shmop --enable-sysvsem --enable-inline-optimization --with-curl --with-curlwrappers --enable-mbregex --enable-fastcgi --enable-fpm --enable-force-cgi-redirect --enable-mbstring --with-mcrypt --enable-ftp --with-gd --enable-gd-native-ttf --with-openssl --with-mhash --enable-pcntl --enable-sockets --with-xmlrpc --enable-zip --enable-soap --without-pear --with-gettext --with-mime-magic
还是yum安装：
================================================================================
Package Arch Version Repository Size
================================================================================
Installing:
php x86_64 5.5.-.fc20 updates 2.6 M
Updating:
php-bcmath x86_64 5.5.-.fc20 updates k
php-devel x86_64 5.5.-.fc20 updates 2.2 M
php-gd x86_64 5.5.-.fc20 updates k
php-imap x86_64 5.5.-.fc20 updates k
php-ldap x86_64 5.5.-.fc20 updates k
php-mbstring x86_64 5.5.-.fc20 updates k
php-mcrypt x86_64 5.5.-.fc20 updates k
php-pdo x86_64 5.5.-.fc20 updates k
php-pgsql x86_64 5.5.-.fc20 updates k
php-process x86_64 5.5.-.fc20 updates k
php-soap x86_64 5.5.-.fc20 updates k
php-xml x86_64 5.5.-.fc20 updates k
Updating for dependencies:
php-cli x86_64 5.5.-.fc20 updates 2.6 M
php-common x86_64 5.5.-.fc20 updates 1.0 M
安装的这些模块都是什么，干什么用的？
分别搜索之，备忘如下：
================================================================================
Package Arch Version Repository Size
================================================================================
Installing:
php PHP主程序
Updating:
php-bcmath 高精度数学函数
php-devel PHP开发库
php-gd 图形开发库
php-imap internet message access protocol,即网际网络信息存取协议
php-ldap 轻量级目录访问协议(Lightweight Directory Access Protocol)
php-mbstring 多字节字符串，比如：中文
php-mcrypt 加密相关函数库
php-pdo PDO数据库操作库
php-pgsql PDO数据库操作库，pg数据库
php-process 进程相关，具体不详
php-soap SOAP 简单对象访问协议
php-xml XML
php-cli php的命令行支持
php-common
更多待补充：