1、NVM 简介

• NVM（node version manager）是一个可以让你在同一台机器上安装和切换不同版本 node 的工具。

• GitHub 地址

2、NVM 环境配置

2.1 安装 NVM

• 如果系统没有安装 git 的话，需先安装 git。

• 在终端输入以下命令安装 NVM。

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

• 安装完成后在终端中输入以下命令配置环境变量。

  # 打开环境变量配置文件
  $ vim ~/.bash_profile

• 在 .bash_profile 文件中添加一下字段。

  source ~/.bashrc

• 保存文件退出，在终端中输入以下命令使配置生效。

  # 使环境变量配置生效
  $ source ~/.bash_profile

2.2 NVM 常用命令

• 常用命令

  # 查看该系统已经安装的版本，这个命令也能看到当前使用的是哪个版本
  $ nvm ls
  
  # 列出全部可以安装的版本号
  $ nvm ls-remote
  
  # 安装指定版本
  $ nvm install [version]
  $ nvm install v10.2.0
  
  # 切换到指定版本，切换效果是全局的
  $ nvm use [version]
  $ nvm use v10.2.0
  
  # 查看当前使用的版本
  $ nvm current

  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 installed 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
      --skip-default-packages                 When installing, skip the default-packages file if it exists
      --latest-npm                            After installing, attempt to upgrade to the latest working npm on the given node version
    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 install-latest-npm                    Attempt to upgrade to the latest working `npm` on the current node version
    nvm reinstall-packages <version>          Reinstall global `npm` packages contained in <version> to current version
    nvm unload                                Unload `nvm` from shell
    nvm which [current | <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 8.0.0                     Install a specific version number
    nvm use 8.0                           Use the latest available 8.0.x release
    nvm run 6.10.3 app.js                 Run app.js using node 6.10.3
    nvm exec 4.8.3 node app.js            Run `node app.js` with the PATH pointing to node 4.8.3
    nvm alias default 8.1.0               Set default node version on a shell
    nvm alias default node                Always default to the latest available node version on a shell
  
  Note:
    to remove, delete, or uninstall nvm - just remove the `$NVM_DIR` folder (usually `~/.nvm`)