未知原因在centos下安装spm-yuan的时候一直无法成功，报错信息如下：

EACCES, permission denied '/root/.spm'
  you need install spm to register the program

    $ npm install spm -g

  if you have installed spm, it maybe you haven't set a NODE_PATH environment variable

搜了一圈，基本上是说

if you have installed spm, it maybe you haven’t set a NODE_PATH environment variable

我想环境变量应该没有问题，其他node模块都正常运行着

[root@localhost ~]# echo $NODE_PATH
/usr/local/lib/node_modules

一直没有找到合适的从问题本质上解决的方案，根据Github上网友phpgcs提供的方案解决(https://github.com/spmjs/spm-build/issues/18)

[root@localhost ~]# chmod 775 /root/.spm -R
[root@localhost ~]# npm install spm-yuan -g

安装顺利没有报错，不过跑spm yuan服务的时候提示：

[root@localhost ~]# spm yuan
Prepare repository...

fs.js:654
  return binding.readdir(pathModule._makeLong(path));
                 ^
Error: ENOENT, no such file or directory '/root/.spm/cache'
    at Object.fs.readdirSync (fs.js:654:18)
    at Object.prepareSpmCacheDir (/usr/local/lib/node_modules/spm-yuan/lib/base/util.js:21:18)
    at module.exports (/usr/local/lib/node_modules/spm-yuan/index.js:18:14)
    at Object. (/usr/local/lib/node_modules/spm-yuan/bin/spm-yuan:43:5)
    at Module._compile (module.js:456:26)
    at Object.Module._extensions..js (module.js:474:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:312:12)
    at Function.Module.runMain (module.js:497:10)
    at startup (node.js:119:16)

直接切换到.spm下建一个cache目录即可

[root@localhost ~]# cd .spm
[root@localhost .spm]# mkdir cache
[root@localhost ~]# spm yuan
Prepare repository...
Start spm-yuan on port 3000

搞定。