就像NPM的官网（）上介绍的那样，安装NPM仅仅是一行命令的事情：

curl http://npmjs.org/install.sh | sh

这里详解一下这句命令的意思，curl http://npmjs.org/install.sh是通过curl命令获取这个安装shell脚本，按后通过管道符| 将获取的脚本交由sh命令来执行。这里如果没有权限会安装不成功，需要加上sudo来确保权限：

curl http://npmjs.org/install.sh | sudo sh

安装成功后执行npm命令，会得到一下的提示：

Usage: npm where  is one of:adduser, apihelp, author, bin, bugs, c, cache, completion,config, deprecate, docs, edit, explore, faq, find, get,help, help-search, home, i, info, init, install, la, link,list, ll, ln, ls, outdated, owner, pack, prefix, prune,publish, r, rb, rebuild, remove, restart, rm, root,run-script, s, se, search, set, show, star, start, stop,submodule, tag, test, un, uninstall, unlink, unpublish,unstar, up, update, version, view, whoami

我们以underscore为例，来展示下通过npm安装第三方包的过程。

npm install underscore

返回：

underscore@1.2.2 ./node_modules/underscore

由于一些特殊的网络环境，直接通过npm install命令安装第三方库的时候，经常会出现卡死的状态。幸运的是国内CNode社区的同学利用空余时间搭建了一个镜像的NPM资源库，服务器架设在日本，可以绕过某些不必要的网络问题。你可以通过以下这条命令来安装第三方库：

npm --registry "" install underscore

如果你想将它设为默认的资源库，运行下面这条命令即可：

npm config set registry “”

设置之后每次安装时就可以不用带上—registry参数。值得一提的是还有另一个镜像可用，该镜像地址是，如需使用，替换上面两行命令的地址即可。

实际实践结果如下：

输入安装NPM的命令之后 有点慢。。哈

tar=/bin/tarversion:tar (GNU tar) 1.15.1fetching: http://registry.npmjs.org/npm/-/npm-1.0.106.tgz0.6.31.0.106cleanup prefix=/usr/localAll clean!/usr/local/bin/npm -> /usr/local/lib/node_modules/npm/bin/npm-cli.js/usr/local/bin/npm-g -> /usr/local/lib/node_modules/npm/bin/npm-cli.js/usr/local/bin/npm_g -> /usr/local/lib/node_modules/npm/bin/npm-cli.jsnpm@1.0.106 /usr/local/lib/node_modules/npmIt worked

安装完成输入 NPM 测试 结果如下

[root@YX-MID node-v0.6.3]# npmUsage: npm where  is one of:    adduser, apihelp, author, bin, bugs, c, cache, completion,    config, deprecate, docs, edit, explore, faq, find, get,    help, help-search, home, i, info, init, install, la, link,    list, ll, ln, ls, outdated, owner, pack, prefix, prune,    publish, r, rb, rebuild, remove, restart, rm, root,    run-script, s, se, search, set, show, star, start, stop,    submodule, tag, test, un, uninstall, unlink, unpublish,    unstar, up, update, version, view, whoaminpm 
    
      -h     quick help on 
     
      npm -l           display full usage infonpm faq          commonly asked questionsnpm help 
      
         search for help on 
       
        npm help npm     involved overviewSpecify configs in the ini-formatted file:    /root/.npmrcor on the command line via: npm 
         --key valueConfig info can be viewed via: npm help config