ldconfig命令-检查linux下的库文件的强大命令

一台跑lnmp的Cent OS出现了故障，本来服务器使用的是编译版本的mysql,但是却阴差阳错的又用yum装了一个，安装后发现有问题，于是再次卸载，卸载后重新编译安装mysql，发现php-fpm无法启动了，提示以下内容

Starting php_fpm /usr/local/php/bin/php-cgi: error while loading shared libraries: libmysqlclient.so.16: cannot open shared object file: No such file or directory

首先检查/etc/ld.so.conf，里面自定义了mysql库目录为/usr/local/mysql/lib/mysql/

检查该目录，发现文件都在，再用ldconfig命令来检查库文件的加载情况

ldconfig

ldconfig: /usr/local/mysql/lib/mysql/libmysqlclient_r.so.16 is not a symbolic link

ldconfig: /usr/local/mysql/lib/mysql/libmysqlclient.so.16 is not a symbolic link

提示两个so文件不是符号链接，这时再用ldconfig -v来查看两个文件链接的目标
ldconfig -v

/usr/local/mysql/lib/mysql:
ldconfig: /usr/local/mysql/lib/mysql/libmysqlclient_r.so.16 is not a symbolic link

    libmysqlclient_r.so.16 -> libmysqlclient_r.so.16.0.0
ldconfig: /usr/local/mysql/lib/mysql/libmysqlclient.so.16 is not a symbolic link

    libmysqlclient.so.16 -> libmysqlclient.so.16.0.0

弄清楚链接的目标之后，重新制作符号链接

ln -s libmysqlclient_r.so.16 libmysqlclient_r.so.16.0.0

ls -s libmysqlclient.so.16 libmysqlclient.so.16.0.0

再次启动php-fpm,问题解决.