1. 下面介绍一个memcached执行失败的问提
启动memcached时报错：
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| error while loading shared libraries: libevent-2.1.so.6
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下面给出解决办法：
1.用ldd命令查看 memcached 命令缺失什么库
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| [root@Autumn ~]# ldd /usr/local/bin/memcached
linux-vdso.so.1 => (0x00007ffc517cf000)
libevent-2.1.so.6 => not found
libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f6c96860000)
libc.so.6 => /lib64/libc.so.6 (0x00007f6c96493000)
/lib64/ld-linux-x86-64.so.2 (0x00007f6c96a7c000)
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2.在安装libevent时，安装结果告诉我们libevent安装在/usr/local/lib/，可以用locate命令查看:
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| locate libevent-2.1.so.6
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如果没有安装locate，请查看：yum安装locate命令。
3.查看 memcached 查找依赖库的路径：
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| [root@Autumn ~]# LD_DEBUG=libs /usr/local/bin/memcached -v
30708: find library=libevent-2.1.so.6 [0]; searching
30708: search cache=/etc/ld.so.cache
30708: search path=/lib64/tls/x86_64:/lib64/tls:/lib64/x86_64:/lib64:/usr/lib64/tls/x86_64:/usr/lib64/tls:/usr/lib64/x86_64:/usr/lib64 (system search path)
30708: trying file=/lib64/tls/x86_64/libevent-2.1.so.6
30708: trying file=/lib64/tls/libevent-2.1.so.6
30708: trying file=/lib64/x86_64/libevent-2.1.so.6
30708: trying file=/lib64/libevent-2.1.so.6
30708: trying file=/usr/lib64/tls/x86_64/libevent-2.1.so.6
30708: trying file=/usr/lib64/tls/libevent-2.1.so.6
30708: trying file=/usr/lib64/x86_64/libevent-2.1.so.6
30708: trying file=/usr/lib64/libevent-2.1.so.6
30708:
/usr/local/bin/memcached: error while loading shared libraries: libevent-2.1.so.6: cannot open shared object file: No such file or directory
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发现它查找了search path那一行后面的路径，我们将libevent-2.1.so.6链接到/lib64目录下：
4.链接libevent-2.1.so.6：
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| $ sudo ln -s /usr/local/lib/libevent-2.1.so.6 /usr/lib64/libevent-2.1.so.6
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