安装nodejs 不管打什么命令都是提示Usage: npm

逛了一圈网上，根据他们写的教程走了一遍，安装下来会发现，npm -v都会提示

Usage: npm 

where  is one of:
    access, adduser, audit, bin, bugs, c, cache, ci, cit,
    completion, config, create, ddp, dedupe, deprecate,
    dist-tag, docs, doctor, edit, explore, get, help,
    help-search, hook, i, init, install, install-test, it, link,
    list, ln, login, logout, ls, outdated, owner, pack, ping,
    prefix, profile, prune, publish, rb, rebuild, repo, restart,
    root, run, run-script, s, se, search, set, shrinkwrap, star,
    stars, start, stop, t, team, test, token, tst, un,
    uninstall, unpublish, unstar, up, update, v, version, view,
    whoami

npm  -h  quick help on 
npm -l            display full usage info
npm help    search for help on 
npm help npm      involved overview

Specify configs in the ini-formatted file:
    /root/.npmrc
or on the command line via: npm  --key value
Config info can be viewed via: npm help config

搞不清为什么，最后终于找到一个方法可以安装nodejs，我是在centos7下，希望能帮到大家
删除之前安装的nodejs，然后在su权限下敲入

curl -sL https://rpm.nodesource.com/setup_5.x  |  bash  -
sudo yum install -y nodejs

此时，node和npm还没加入环境
找到nodejs下node和npm命令

find / -name node
#或者
whereis node

假设这是node地址，建立软链接

ln -s /usr/bin/node
ln -s /usr/bin/npm

完成，查看版本

node -v
npm -v