简单说明

NVM全称为Node Version Manager，是一个存放在github上的工具，用于管理Node.js版本，如果要使用Node.js则建议先安装NVM。在github上有对nvm详细的描述。github地址：https://github.com/creationix/nvm。

安装NVM（依赖GIT，请确保已安装GIT）

一、运行命令

$ curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.33.11/install.sh | bash

或者

$ wget -qO- https://raw.githubusercontent.com/creationix/nvm/v0.33.11/install.sh | bash

建议使用curl的方式，安装后将创建目录~/.nvm并将内容存放在这里。
命令执行时注意查看日志，如下图说明缺少环境变量配置

• 第一处提示在~/.bashrc, ~/.bash_profile, ~/.zshrc, ~/.profile都没有找到所需要的配置信息。
• 第二处提示我们可以将export NVM_DIR...这两句句命令添加到恰当的文件中，也就是上面列出的四个文件中的一个。
• 第三处的意思就是如果现在需要使用nvm，可以直接执行如下命令，然后就可以使用nvm了（这种方式在重新启动Terminal以后无法继续使用nvm）。

为了方便，我把这几句命令提取出来如下：

export NVM_DIR="$HOME/.nvm"
[ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh"  # This loads nvm
[ -s "$NVM_DIR/bash_completion" ] && \. "$NVM_DIR/bash_completion"  # This loads nvm bash_completion

二、经过第一步的分析，需要将以上代码添加至~/.bash_profile或者~/.profile文件中

为了能够在重启（在Mac上则为重启Terminal）以后还能继续使用NVM，我们可以把这段配置信息添加到~/.bash_profile或者~/.profile文件中，经过实践测试添加到~/.bashrc或~/.zshrc文件中均无法在重启Terminal后使用NVM。

具体操作如下：

$ cd ~
$ vim .bash_profile
## 将export NVM_DIR ... 粘贴到文件中
## ESC -> 键入":" -> 键入"wq" -> 回车保存
## 让配置文件里面生效
$ source .bash_profile

完成后运行nvm测试，如输出如下说明已安装成功

$ nvm 

Node Version Manager

Note: <version> refers to any version-like string nvm understands. This includes:
  - full or partial version numbers, starting with an optional "v" (0.10, v0.1.2, v1)
  - default (built-in) aliases: node, stable, unstable, iojs, system
  - custom aliases you define with `nvm alias foo`

 Any options that produce colorized output should respect the `--no-colors` option.

Usage:
  nvm --help                                Show this message
  nvm --version                             Print out the latest released version of nvm
  nvm install [-s] <version>                Download and install a <version>, [-s] from source. Uses .nvmrc if available
    --reinstall-packages-from=<version>     When installing, reinstall packages installed in <node|iojs|node version number>
    --lts                                   When installing, only select from LTS (long-term support) versions
    --lts=<LTS name>                        When installing, only select from versions for a specific LTS line
  nvm uninstall <version>                   Uninstall a version
  nvm uninstall --lts                       Uninstall using automatic LTS (long-term support) alias `lts/*`, if available.
  nvm uninstall --lts=<LTS name>            Uninstall using automatic alias for provided LTS line, if available.
  nvm use [--silent] <version>              Modify PATH to use <version>. Uses .nvmrc if available
    --lts                                   Uses automatic LTS (long-term support) alias `lts/*`, if available.
    --lts=<LTS name>                        Uses automatic alias for provided LTS line, if available.
  nvm exec [--silent] <version> [<command>] Run <command> on <version>. Uses .nvmrc if available
    --lts                                   Uses automatic LTS (long-term support) alias `lts/*`, if available.
    --lts=<LTS name>                        Uses automatic alias for provided LTS line, if available.
  nvm run [--silent] <version> [<args>]     Run `node` on <version> with <args> as arguments. Uses .nvmrc if available
    --lts                                   Uses automatic LTS (long-term support) alias `lts/*`, if available.
    --lts=<LTS name>                        Uses automatic alias for provided LTS line, if available.
  nvm current                               Display currently activated version
  nvm ls                                    List installed versions
  nvm ls <version>                          List versions matching a given <version>
  nvm ls-remote                             List remote versions available for install
    --lts                                   When listing, only show LTS (long-term support) versions
  nvm ls-remote <version>                   List remote versions available for install, matching a given <version>
    --lts                                   When listing, only show LTS (long-term support) versions
    --lts=<LTS name>                        When listing, only show versions for a specific LTS line
  nvm version <version>                     Resolve the given description to a single local version
  nvm version-remote <version>              Resolve the given description to a single remote version
    --lts                                   When listing, only select from LTS (long-term support) versions
    --lts=<LTS name>                        When listing, only select from versions for a specific LTS line
  nvm deactivate                            Undo effects of `nvm` on current shell
  nvm alias [<pattern>]                     Show all aliases beginning with <pattern>
  nvm alias <name> <version>                Set an alias named <name> pointing to <version>
  nvm unalias <name>                        Deletes the alias named <name>
  nvm reinstall-packages <version>          Reinstall global `npm` packages contained in <version> to current version
  nvm unload                                Unload `nvm` from shell
  nvm which [<version>]                     Display path to installed node version. Uses .nvmrc if available
  nvm cache dir                             Display path to the cache directory for nvm
  nvm cache clear                           Empty cache directory for nvm

Example:
  nvm install v0.10.32                  Install a specific version number
  nvm use 0.10                          Use the latest available 0.10.x release
  nvm run 0.10.32 app.js                Run app.js using node v0.10.32
  nvm exec 0.10.32 node app.js          Run `node app.js` with the PATH pointing to node v0.10.32
  nvm alias default 0.10.32             Set default node version on a shell

Note:
  to remove, delete, or uninstall nvm - just remove the `$NVM_DIR` folder (usually `~/.nvm`)

卸载NVM

执行下面的命令移除nvm内容

cd ~
rm -rf .nvm

移除掉~/.profile, ~/.bash_profile, ~/.zshrc, ~/.bashrc文件中关于nvm的配置