安装memcache时，需要建立文件索引或者说文件连接（link），类似windows下的快捷方式
启动服务时出现 error while loading shared libraries: libevent-2.0.so.5: cannot open shared object file: No such file or directory
>whereis libevent-2.0.so.5
libevent-2.0.so.5: /usr/local/lib/libevent-2.0.so.5
> ldd /usr/local/bin/memcached （ldd指令不熟悉的去查看下）
libevent-2.0.so.5 => not found （没有找到该文件）
libpthread.so.0 => /lib64/libpthread.so.0 (0x00002b83fce0e000)
libc.so.6 => /lib64/libc.so.6 (0x00002b83fd029000)
librt.so.1 => /lib64/librt.so.1 (0x00002b83fd381000)
/lib64/ld-linux-x86-64.so.2 (0x00002b83fc9b0000)
> LD_DEBUG=libs ./memcached -v
找到默认路径 /usr/lib/
>sudo ln -s /usr/local/lib/libevent-2.0.so.5 /usr/lib64/libevent-2.0.so.5
>sudo ldd /usr/local/bin/memcached
libevent-2.0.so.5 => /