From f39b6932b1dfba653519103944277d3e6d72b07d Mon Sep 17 00:00:00 2001
From: ULIVZ <472590061@qq.com>
Date: Tue, 4 Dec 2018 23:54:41 +0800
Subject: [PATCH 01/10] chore: show-help script

---
 package.json               | 1 +
 packages/docs/package.json | 3 ++-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/package.json b/package.json
index d204b21bbc..3c8473c60d 100644
--- a/package.json
+++ b/package.json
@@ -12,6 +12,7 @@
     "boot": "node scripts/bootstrap.js",
     "dev": "yarn workspace docs dev",
     "build": "yarn workspace docs build",
+    "show-help": "yarn workspace docs show-help",
     "dev:blog": "yarn workspace blog dev",
     "build:blog": "yarn workspace blog build",
     "register-vuepress": "lerna exec --scope vuepress -- yarn link",
diff --git a/packages/docs/package.json b/packages/docs/package.json
index 771ad7a83f..175e3ef5f5 100644
--- a/packages/docs/package.json
+++ b/packages/docs/package.json
@@ -5,7 +5,8 @@
   "description": "docs of VuePress",
   "scripts": {
     "dev": "vuepress dev docs --temp .temp",
-    "build": "vuepress build docs --temp .temp"
+    "build": "vuepress build docs --temp .temp",
+    "show-help": "vuepress --help"
   },
   "repository": {
     "type": "git",

From bc57ec96edaa1ae26703a2ce8b7f4ee017d3ec3f Mon Sep 17 00:00:00 2001
From: ULIVZ <472590061@qq.com>
Date: Wed, 5 Dec 2018 01:58:40 +0800
Subject: [PATCH 02/10] feat: new plugin option API - 'registerCommand'

Internal changes:

1. Removing '@vuepress/cli' package
---
 .gitignore                                    |   1 -
 packages/@vuepress/cli/.npmignore             |   3 -
 packages/@vuepress/cli/README.md              |  18 ---
 packages/@vuepress/cli/index.js               | 129 -----------------
 packages/@vuepress/cli/package.json           |  39 -----
 packages/@vuepress/core/lib/index.js          |   1 +
 .../core/lib/plugin-api/constants.js          |   3 +-
 .../@vuepress/core/lib/plugin-api/index.js    |   4 +-
 .../@vuepress/core/lib/prepare/AppContext.js  |   1 +
 packages/@vuepress/core/lib/unknownCommand.js |  11 ++
 packages/vuepress/lib/checkEnv.js             |  26 ++++
 packages/vuepress/lib/handleUnknownCommand.js | 133 ++++++++++++++++++
 packages/vuepress/lib/registerCoreCommands.js |  67 +++++++++
 packages/vuepress/lib/util.js                 |  56 ++++++++
 packages/vuepress/vuepress.js                 |  27 +++-
 15 files changed, 326 insertions(+), 193 deletions(-)
 delete mode 100644 packages/@vuepress/cli/.npmignore
 delete mode 100644 packages/@vuepress/cli/README.md
 delete mode 100644 packages/@vuepress/cli/index.js
 delete mode 100644 packages/@vuepress/cli/package.json
 create mode 100644 packages/@vuepress/core/lib/unknownCommand.js
 create mode 100644 packages/vuepress/lib/checkEnv.js
 create mode 100644 packages/vuepress/lib/handleUnknownCommand.js
 create mode 100644 packages/vuepress/lib/registerCoreCommands.js
 create mode 100644 packages/vuepress/lib/util.js

diff --git a/.gitignore b/.gitignore
index 9a60952a32..9496595310 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,4 +3,3 @@ node_modules
 *.log
 .temp
 TODOs.md
-vuepress
diff --git a/packages/@vuepress/cli/.npmignore b/packages/@vuepress/cli/.npmignore
deleted file mode 100644
index 13c38ea313..0000000000
--- a/packages/@vuepress/cli/.npmignore
+++ /dev/null
@@ -1,3 +0,0 @@
-__tests__
-__mocks__
-.temp
diff --git a/packages/@vuepress/cli/README.md b/packages/@vuepress/cli/README.md
deleted file mode 100644
index e2524b698b..0000000000
--- a/packages/@vuepress/cli/README.md
+++ /dev/null
@@ -1,18 +0,0 @@
-# @vuepress/cli
-
-> cli for vuepress
-
-## APIs
-
-### program
-
-Current instance of [commander.js](https://github.com/tj/commander.js)
-
-### bootstrap(options)
-
-Launch the cli.
-
-#### options.plugins
-
-#### options.theme
-         
\ No newline at end of file
diff --git a/packages/@vuepress/cli/index.js b/packages/@vuepress/cli/index.js
deleted file mode 100644
index c132a7b310..0000000000
--- a/packages/@vuepress/cli/index.js
+++ /dev/null
@@ -1,129 +0,0 @@
-const { chalk } = require('@vuepress/shared-utils')
-const semver = require('semver')
-
-try {
-  require.resolve('@vuepress/core')
-} catch (err) {
-  console.log(chalk.red(
-    `\n[vuepress] @vuepress/cli ` +
-    `requires @vuepress/core to be installed.\n`
-  ))
-  process.exit(1)
-}
-
-const pkg = require('@vuepress/core/package.json')
-const requiredVersion = pkg.engines.node
-
-if (!semver.satisfies(process.version, requiredVersion)) {
-  console.log(chalk.red(
-    `\n[vuepress] minimum Node version not met:` +
-    `\nYou are using Node ${process.version}, but VuePress ` +
-    `requires Node ${requiredVersion}.\nPlease upgrade your Node version.\n`
-  ))
-  process.exit(1)
-}
-
-const cli = require('cac')()
-
-exports.cli = cli
-exports.bootstrap = function ({
-  plugins,
-  theme
-} = {}) {
-  const { path, logger, env } = require('@vuepress/shared-utils')
-  const { dev, build, eject } = require('@vuepress/core')
-
-  cli
-    .version(pkg.version)
-    .help()
-
-  cli
-    .command('dev [targetDir]', 'start development server')
-    .option('-p, --port <port>', 'use specified port (default: 8080)')
-    .option('-t, --temp <temp>', 'set the directory of the temporary file')
-    .option('-c, --cache [cache]', 'set the directory of cache')
-    .option('--host <host>', 'use specified host (default: 0.0.0.0)')
-    .option('--no-cache', 'clean the cache before build')
-    .option('--debug', 'start development server in debug mode')
-    .option('--silent', 'start development server in silent mode')
-    .action((sourceDir = '.', options) => {
-      const {
-        host,
-        port,
-        debug,
-        temp,
-        cache,
-        silent
-      } = options
-      logger.setOptions({ logLevel: silent ? 1 : debug ? 4 : 3 })
-      logger.debug('cli_options', options)
-      env.setOptions({ isDebug: debug, isTest: process.env.NODE_ENV === 'test' })
-
-      wrapCommand(dev)(path.resolve(sourceDir), {
-        host,
-        port,
-        temp,
-        cache,
-        plugins,
-        theme
-      })
-    })
-
-  cli
-    .command('build [targetDir]', 'build dir as static site')
-    .option('-d, --dest <dest>', 'specify build output dir (default: .vuepress/dist)')
-    .option('-t, --temp <temp>', 'set the directory of the temporary file')
-    .option('-c, --cache [cache]', 'set the directory of cache')
-    .option('--no-cache', 'clean the cache before build')
-    .option('--debug', 'build in development mode for debugging')
-    .option('--silent', 'build static site in silent mode')
-    .action((sourceDir = '.', options) => {
-      const {
-        debug,
-        dest,
-        temp,
-        cache,
-        silent
-      } = options
-      logger.setOptions({ logLevel: silent ? 1 : debug ? 4 : 3 })
-      logger.debug('cli_options', options)
-      env.setOptions({ isDebug: debug, isTest: process.env.NODE_ENV === 'test' })
-
-      wrapCommand(build)(path.resolve(sourceDir), {
-        debug,
-        dest,
-        plugins,
-        theme,
-        temp,
-        cache,
-        silent
-      })
-    })
-
-  cli
-    .command('eject [targetDir]', 'copy the default theme into .vuepress/theme for customization.')
-    .option('--debug', 'eject in debug mode')
-    .action((dir = '.') => {
-      wrapCommand(eject)(path.resolve(dir))
-    })
-
-  // output help information on unknown commands
-  cli.on('command:*', () => {
-    console.error('Unknown command: %s', cli.args.join(' '))
-    console.log()
-  })
-
-  function wrapCommand (fn) {
-    return (...args) => {
-      return fn(...args).catch(err => {
-        console.error(chalk.red(err.stack))
-        process.exitCode = 1
-      })
-    }
-  }
-
-  cli.parse(process.argv)
-  if (!process.argv.slice(2).length) {
-    cli.outputHelp()
-  }
-}
diff --git a/packages/@vuepress/cli/package.json b/packages/@vuepress/cli/package.json
deleted file mode 100644
index 72a5b3b27f..0000000000
--- a/packages/@vuepress/cli/package.json
+++ /dev/null
@@ -1,39 +0,0 @@
-{
-  "name": "@vuepress/cli",
-  "version": "1.0.0-alpha.24",
-  "description": "cli for vuepress",
-  "main": "index.js",
-  "publishConfig": {
-    "access": "public"
-  },
-  "repository": {
-    "type": "git",
-    "url": "git+https://github.com/vuejs/vue-cli.git"
-  },
-  "keywords": [
-    "documentation",
-    "vue",
-    "vuepress",
-    "generator"
-  ],
-  "author": "Evan You",
-  "maintainers": [
-    {
-      "name": "ULIVZ",
-      "email": "chl814@foxmail.com"
-    }
-  ],
-  "license": "MIT",
-  "bugs": {
-    "url": "https://github.com/vuejs/vuepress/issues"
-  },
-  "dependencies": {
-    "chalk": "^2.3.2",
-    "semver": "^5.5.0",
-    "cac": "^6.3.3"
-  },
-  "peerDependencies": {
-    "@vuepress/core": "^1.0.0-alpha.1"
-  },
-  "homepage": "https://github.com/vuejs/vuepress/packages/@vuepress/cli#readme"
-}
diff --git a/packages/@vuepress/core/lib/index.js b/packages/@vuepress/core/lib/index.js
index 43a6d0124b..522ff40069 100644
--- a/packages/@vuepress/core/lib/index.js
+++ b/packages/@vuepress/core/lib/index.js
@@ -3,3 +3,4 @@
 exports.dev = require('./dev')
 exports.build = require('./build')
 exports.eject = require('./eject')
+exports.unknownCommand = require('./unknownCommand')
diff --git a/packages/@vuepress/core/lib/plugin-api/constants.js b/packages/@vuepress/core/lib/plugin-api/constants.js
index e9bcb63591..55d92c8d5a 100644
--- a/packages/@vuepress/core/lib/plugin-api/constants.js
+++ b/packages/@vuepress/core/lib/plugin-api/constants.js
@@ -19,7 +19,8 @@ const PLUGIN_OPTION_META_MAP = {
   ADDITIONAL_PAGES: { name: 'additionalPages', types: [Function, Array] },
   GLOBAL_UI_COMPONENTS: { name: 'globalUIComponents', types: [String, Array] },
   DEFINE: { name: 'define', types: [Function, Object] },
-  ALIAS: { name: 'alias', types: [Function, Object] }
+  ALIAS: { name: 'alias', types: [Function, Object] },
+  REGISTER_COMMAND: { name: 'registerCommand', types: [Function] }
 }
 
 const PLUGIN_OPTION_MAP = {}
diff --git a/packages/@vuepress/core/lib/plugin-api/index.js b/packages/@vuepress/core/lib/plugin-api/index.js
index 7158e8e87b..c7f0f8c815 100644
--- a/packages/@vuepress/core/lib/plugin-api/index.js
+++ b/packages/@vuepress/core/lib/plugin-api/index.js
@@ -207,7 +207,8 @@ module.exports = class PluginAPI {
     additionalPages,
     globalUIComponents,
     define,
-    alias
+    alias,
+    registerCommand
   }) {
     const isInternalPlugin = pluginName.startsWith('@vuepress/internal-')
     if (!isInternalPlugin || debug) {
@@ -236,5 +237,6 @@ module.exports = class PluginAPI {
       .registerOption(PLUGIN_OPTION_MAP.GLOBAL_UI_COMPONENTS.key, globalUIComponents, pluginName)
       .registerOption(PLUGIN_OPTION_MAP.DEFINE.key, define, pluginName)
       .registerOption(PLUGIN_OPTION_MAP.ALIAS.key, alias, pluginName)
+      .registerOption(PLUGIN_OPTION_MAP.REGISTER_COMMAND.key, registerCommand, pluginName)
   }
 }
diff --git a/packages/@vuepress/core/lib/prepare/AppContext.js b/packages/@vuepress/core/lib/prepare/AppContext.js
index fe04d23fdc..cd790098ff 100644
--- a/packages/@vuepress/core/lib/prepare/AppContext.js
+++ b/packages/@vuepress/core/lib/prepare/AppContext.js
@@ -36,6 +36,7 @@ module.exports = class AppContext {
    */
 
   constructor (sourceDir, cliOptions = {}, isProd) {
+    logger.debug('sourceDir', sourceDir)
     this.sourceDir = sourceDir
     this.cliOptions = cliOptions
     this.isProd = isProd
diff --git a/packages/@vuepress/core/lib/unknownCommand.js b/packages/@vuepress/core/lib/unknownCommand.js
new file mode 100644
index 0000000000..89c8cba18c
--- /dev/null
+++ b/packages/@vuepress/core/lib/unknownCommand.js
@@ -0,0 +1,11 @@
+'use strict'
+
+module.exports = async function (commandName, sourceDir, cliOptions = {}) {
+  const prepare = require('./prepare/index')
+  const ctx = await prepare(sourceDir, cliOptions, false /* isProd */)
+  const cli = require('cac')()
+  cli.help()
+  ctx.pluginAPI.options.registerCommand.apply(cli)
+  cli.parse()
+  return cli
+}
diff --git a/packages/vuepress/lib/checkEnv.js b/packages/vuepress/lib/checkEnv.js
new file mode 100644
index 0000000000..3fe1feb6fc
--- /dev/null
+++ b/packages/vuepress/lib/checkEnv.js
@@ -0,0 +1,26 @@
+module.exports = function checkEnv () {
+  const { chalk } = require('@vuepress/shared-utils')
+  const semver = require('semver')
+
+  try {
+    require.resolve('@vuepress/core')
+  } catch (err) {
+    console.log(chalk.red(
+      `\n[vuepress] @vuepress/cli ` +
+      `requires @vuepress/core to be installed.\n`
+    ))
+    process.exit(1)
+  }
+
+  const pkg = require('@vuepress/core/package.json')
+  const requiredVersion = pkg.engines.node
+
+  if (!semver.satisfies(process.version, requiredVersion)) {
+    console.log(chalk.red(
+      `\n[vuepress] minimum Node version not met:` +
+      `\nYou are using Node ${process.version}, but VuePress ` +
+      `requires Node ${requiredVersion}.\nPlease upgrade your Node version.\n`
+    ))
+    process.exit(1)
+  }
+}
diff --git a/packages/vuepress/lib/handleUnknownCommand.js b/packages/vuepress/lib/handleUnknownCommand.js
new file mode 100644
index 0000000000..0394e9bf4a
--- /dev/null
+++ b/packages/vuepress/lib/handleUnknownCommand.js
@@ -0,0 +1,133 @@
+'use strict'
+
+/**
+ * Module dependencies.
+ */
+
+const prepare = require('@vuepress/core/lib/prepare')
+const { path, logger, globby, chalk } = require('@vuepress/shared-utils')
+const { isKnownCommand, CLI } = require('./util')
+const pwd = process.cwd()
+
+/**
+ * Expose handleUnknownCommand function.
+ */
+
+module.exports = async function (cli, options) {
+  registerUnknownCommands(cli, options)
+
+  const argv = process.argv.slice(2)
+  const inferredUserDocsDirectory = await inferUserDocsDirectory(pwd)
+  logger.developer('inferredUserDocsDirectory', inferredUserDocsDirectory)
+
+  const needPrepareBeforeLaunchCLI = inferredUserDocsDirectory &&
+    (isHelpFlag(argv[0]) || isUnknownCommandHelp(argv))
+
+  logger.developer('needPrepareBeforeLaunchCLI', needPrepareBeforeLaunchCLI)
+
+  if (needPrepareBeforeLaunchCLI) {
+    let context
+    let [, sourceDir] = argv
+
+    if (!sourceDir || sourceDir.startsWith('-')) {
+      sourceDir = inferredUserDocsDirectory
+    } else {
+      sourceDir = pwd
+    }
+
+    logger.setOptions({ logLevel: 1 })
+
+    if (sourceDir) {
+      context = await prepare(sourceDir, options)
+      context.pluginAPI.options.registerCommand.apply(cli)
+    }
+
+    logger.setOptions({ logLevel: 3 })
+  }
+}
+
+// When user type `vuepress [customCommand] --help`,
+// VuePress will try to detect where user to place docs.
+
+async function inferUserDocsDirectory (cwd) {
+  const paths = await globby([
+    '**/.vuepress/config.js',
+    '!node_modules'
+  ], {
+    cwd,
+    dot: true
+  })
+  const siteConfigPath = paths && paths[0]
+  if (siteConfigPath) {
+    return path.resolve(
+      cwd,
+      siteConfigPath.replace('.vuepress/config.js', '')
+    )
+  }
+  return null
+}
+
+/**
+ * Register a command to match all unmatched commands
+ * @param {CAC} cli
+ */
+
+function registerUnknownCommands (cli, options) {
+  cli.on('command:*', async () => {
+    const { args, options: commandoptions } = cli
+
+    logger.debug('global_options', options)
+    logger.debug('cli_options', commandoptions)
+    logger.debug('cli_args', args)
+
+    const [commandName] = args
+    const sourceDir = args[1] ? path.resolve(args[1]) : pwd
+    const inferredUserDocsDirectory = await inferUserDocsDirectory(pwd)
+    logger.developer('inferredUserDocsDirectory', inferredUserDocsDirectory)
+    logger.developer('sourceDir', sourceDir)
+
+    if (inferredUserDocsDirectory && sourceDir !== inferredUserDocsDirectory) {
+      logUnknownCommand(cli)
+      console.log()
+      logger.tip(`Did you miss to specify the target docs dir? e.g. ${chalk.cyan(`vuepress ${commandName} [targetDir]`)}.`)
+      logger.tip(`A custom command registered by a plugin requires VuePress to locate your site configuration like ${chalk.cyan('vuepress dev')} or ${chalk.cyan('vuepress build')}.`)
+      console.log()
+      process.exit(1)
+    }
+
+    if (!inferredUserDocsDirectory) {
+      logUnknownCommand(cli)
+      process.exit(1)
+    }
+
+    logger.debug('Custom command', chalk.cyan(commandName))
+    CLI({
+      async beforeParse (subCli) {
+        const context = await prepare(sourceDir, {
+          ...options,
+          ...commandoptions
+        }, false /* isProd */)
+        await context.pluginAPI.options.registerCommand.apply(subCli)
+      },
+      async afterParse (subCli) {
+        if (!subCli.matchedCommand) {
+          logUnknownCommand(subCli)
+          console.log()
+        }
+      }
+    })
+  })
+}
+
+function isHelpFlag (v) {
+  return v === '--help' || v === '-h'
+}
+
+function isUnknownCommandHelp (argv) {
+  return !isKnownCommand(argv) && isHelpFlag(argv[1])
+}
+
+function logUnknownCommand (cli) {
+  console.error('Unknown command: %s', cli.args.join(' '))
+}
+
diff --git a/packages/vuepress/lib/registerCoreCommands.js b/packages/vuepress/lib/registerCoreCommands.js
new file mode 100644
index 0000000000..3301fae914
--- /dev/null
+++ b/packages/vuepress/lib/registerCoreCommands.js
@@ -0,0 +1,67 @@
+'use strict'
+
+/**
+ * Module dependencies.
+ */
+
+const { dev, build, eject } = require('@vuepress/core')
+const { path, logger, env } = require('@vuepress/shared-utils')
+const { wrapCommand } = require('./util')
+
+/**
+ * Expose registerCoreCommands function.
+ */
+
+module.exports = function (cli, options) {
+  cli
+    .command(`dev [targetDir]`, 'start development server')
+    .option('-p, --port <port>', 'use specified port (default: 8080)')
+    .option('-t, --temp <temp>', 'set the directory of the temporary file')
+    .option('-c, --cache [cache]', 'set the directory of cache')
+    .option('--host <host>', 'use specified host (default: 0.0.0.0)')
+    .option('--no-cache', 'clean the cache before build')
+    .option('--debug', 'start development server in debug mode')
+    .option('--silent', 'start development server in silent mode')
+    .action((sourceDir = '.', commandOptions) => {
+      const { debug, silent } = commandOptions
+
+      logger.setOptions({ logLevel: silent ? 1 : debug ? 4 : 3 })
+      logger.debug('global_options', options)
+      logger.debug('dev_options', commandOptions)
+      env.setOptions({ isDebug: debug, isTest: process.env.NODE_ENV === 'test' })
+
+      wrapCommand(dev)(path.resolve(sourceDir), {
+        ...options,
+        ...commandOptions
+      })
+    })
+
+  cli
+    .command('build [targetDir]', 'build dir as static site')
+    .option('-d, --dest <dest>', 'specify build output dir (default: .vuepress/dist)')
+    .option('-t, --temp <temp>', 'set the directory of the temporary file')
+    .option('-c, --cache [cache]', 'set the directory of cache')
+    .option('--no-cache', 'clean the cache before build')
+    .option('--debug', 'build in development mode for debugging')
+    .option('--silent', 'build static site in silent mode')
+    .action((sourceDir = '.', commandOptions) => {
+      const { debug, silent } = commandOptions
+
+      logger.setOptions({ logLevel: silent ? 1 : debug ? 4 : 3 })
+      logger.debug('global_options', options)
+      logger.debug('build_options', commandOptions)
+      env.setOptions({ isDebug: debug, isTest: process.env.NODE_ENV === 'test' })
+
+      wrapCommand(build)(path.resolve(sourceDir), {
+        ...options,
+        ...commandOptions
+      })
+    })
+
+  cli
+    .command('eject [targetDir]', 'copy the default theme into .vuepress/theme for customization.')
+    .option('--debug', 'eject in debug mode')
+    .action((dir = '.') => {
+      wrapCommand(eject)(path.resolve(dir))
+    })
+}
diff --git a/packages/vuepress/lib/util.js b/packages/vuepress/lib/util.js
new file mode 100644
index 0000000000..6c14e277ea
--- /dev/null
+++ b/packages/vuepress/lib/util.js
@@ -0,0 +1,56 @@
+'use strict'
+
+/**
+ * Module dependencies.
+ */
+
+const { chalk } = require('@vuepress/shared-utils')
+const CAC = require('cac')
+
+/**
+ * Bootstrap a CAC cli
+ * @param {function} beforeParse
+ * @param {function} adterParse
+ * @returns {Promise<void>}
+ */
+
+async function CLI ({
+  beforeParse,
+  afterParse
+}) {
+  const cli = CAC()
+  beforeParse && await beforeParse(cli)
+  cli.parse(process.argv)
+  afterParse && await afterParse(cli)
+}
+
+/**
+ * Wrap a function to catch error.
+ * @param {function} fn
+ * @returns {function(...[*]): (*|Promise|Promise<T | never>)}
+ */
+
+function wrapCommand (fn) {
+  return (...args) => {
+    return fn(...args).catch(err => {
+      console.error(chalk.red(err.stack))
+      process.exitCode = 1
+    })
+  }
+}
+
+/**
+ * Check if a command is built-in
+ * @param {array} argv
+ * @returns {boolean}
+ */
+
+function isKnownCommand (argv) {
+  return ['dev', 'build', 'eject'].includes(argv[0])
+}
+
+module.exports = {
+  CLI,
+  isKnownCommand,
+  wrapCommand
+}
diff --git a/packages/vuepress/vuepress.js b/packages/vuepress/vuepress.js
index c885579271..78c9528808 100755
--- a/packages/vuepress/vuepress.js
+++ b/packages/vuepress/vuepress.js
@@ -1,3 +1,28 @@
 #!/usr/bin/env node
 
-require('@vuepress/cli').bootstrap({ theme: '@vuepress/default' })
+const checkEnv = require('./lib/checkEnv')
+const { CLI } = require('./lib/util')
+const registerCoreCommands = require('./lib/registerCoreCommands')
+const handleUnknownCommand = require('./lib/handleUnknownCommand')
+
+const OPTIONS = {
+  theme: '@vuepress/default'
+}
+
+CLI({
+  async beforeParse (cli) {
+    checkEnv()
+    registerCoreCommands(cli, OPTIONS)
+    await handleUnknownCommand(cli, OPTIONS)
+
+    const pkg = require('@vuepress/core/package.json')
+    cli.version(pkg.version).help()
+  },
+
+  async afterParse (cli) {
+    if (!process.argv.slice(2).length) {
+      cli.outputHelp()
+    }
+  }
+})
+

From 239547f91dbb2449336a35274576ff40da9e8570 Mon Sep 17 00:00:00 2001
From: ULIVZ <472590061@qq.com>
Date: Wed, 5 Dec 2018 02:09:10 +0800
Subject: [PATCH 03/10] chore: gitignore

---
 .gitignore | 1 +
 1 file changed, 1 insertion(+)

diff --git a/.gitignore b/.gitignore
index 9496595310..9a60952a32 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,3 +3,4 @@ node_modules
 *.log
 .temp
 TODOs.md
+vuepress

From 9d0d879d3bb8383134547713079ad11364983fea Mon Sep 17 00:00:00 2001
From: ULIVZ <472590061@qq.com>
Date: Wed, 5 Dec 2018 02:13:00 +0800
Subject: [PATCH 04/10] chore: remove unnecessary check and outdated code

---
 packages/vuepress/lib/checkEnv.js | 25 ++++++++++++-------------
 packages/vuepress/package.json    |  1 -
 packages/vuepress/vuepress.js     |  5 ++---
 3 files changed, 14 insertions(+), 17 deletions(-)

diff --git a/packages/vuepress/lib/checkEnv.js b/packages/vuepress/lib/checkEnv.js
index 3fe1feb6fc..8b0de2959c 100644
--- a/packages/vuepress/lib/checkEnv.js
+++ b/packages/vuepress/lib/checkEnv.js
@@ -1,18 +1,17 @@
-module.exports = function checkEnv () {
-  const { chalk } = require('@vuepress/shared-utils')
-  const semver = require('semver')
+'use strict'
 
-  try {
-    require.resolve('@vuepress/core')
-  } catch (err) {
-    console.log(chalk.red(
-      `\n[vuepress] @vuepress/cli ` +
-      `requires @vuepress/core to be installed.\n`
-    ))
-    process.exit(1)
-  }
+/**
+ * Module dependencies.
+ */
+
+const { chalk } = require('@vuepress/shared-utils')
+const semver = require('semver')
+
+/**
+ * Expose handleUnknownCommand function.
+ */
 
-  const pkg = require('@vuepress/core/package.json')
+module.exports = function checkEnv (pkg) {
   const requiredVersion = pkg.engines.node
 
   if (!semver.satisfies(process.version, requiredVersion)) {
diff --git a/packages/vuepress/package.json b/packages/vuepress/package.json
index 76eed6341d..b3981e52db 100644
--- a/packages/vuepress/package.json
+++ b/packages/vuepress/package.json
@@ -28,7 +28,6 @@
   },
   "homepage": "https://github.com/vuejs/vuepress#readme",
   "dependencies": {
-    "@vuepress/cli": "^1.0.0-alpha.24",
     "@vuepress/core": "^1.0.0-alpha.24",
     "@vuepress/theme-default": "^1.0.0-alpha.24"
   },
diff --git a/packages/vuepress/vuepress.js b/packages/vuepress/vuepress.js
index 78c9528808..35050b4f62 100755
--- a/packages/vuepress/vuepress.js
+++ b/packages/vuepress/vuepress.js
@@ -11,11 +11,10 @@ const OPTIONS = {
 
 CLI({
   async beforeParse (cli) {
-    checkEnv()
+    const pkg = require('@vuepress/core/package.json')
+    checkEnv(pkg)
     registerCoreCommands(cli, OPTIONS)
     await handleUnknownCommand(cli, OPTIONS)
-
-    const pkg = require('@vuepress/core/package.json')
     cli.version(pkg.version).help()
   },
 

From 9cd9c738113132561f5c045f1c0bca2fb654d7c0 Mon Sep 17 00:00:00 2001
From: ULIVZ <472590061@qq.com>
Date: Wed, 5 Dec 2018 02:28:45 +0800
Subject: [PATCH 05/10] docs: update

---
 .../docs/miscellaneous/design-concepts.md     |  3 +--
 packages/docs/docs/plugin/option-api.md       | 26 ++++++++++++++++++
 .../docs/zh/miscellaneous/design-concepts.md  |  3 +--
 packages/docs/docs/zh/plugin/option-api.md    | 27 +++++++++++++++++++
 4 files changed, 55 insertions(+), 4 deletions(-)

diff --git a/packages/docs/docs/miscellaneous/design-concepts.md b/packages/docs/docs/miscellaneous/design-concepts.md
index 665c4c2891..1dc40d857a 100644
--- a/packages/docs/docs/miscellaneous/design-concepts.md
+++ b/packages/docs/docs/miscellaneous/design-concepts.md
@@ -187,9 +187,8 @@ Then the final route of i18n UI is `/i18n/`.
 
 ## Others
 
-With the goal of decoupling, we were able to separate VuePress into the following libraries by introducing monorepo:
+With the goal of decoupling, we were able to separate VuePress into the following two libraries by introducing monorepo:
 
-- [@vuepress/cli](https://github.com/vuejs/vuepress/tree/master/packages/@vuepress/cli): Management of command line;
 - [@vuepress/core](https://github.com/vuejs/vuepress/tree/master/packages/@vuepress/core)：Including the core implementation of `dev`, `build` and `Plugin API`;
 - [@vuepress/theme-default](https://github.com/vuejs/vuepress/tree/master/packages/@vuepress/theme-default)：The default theme you see now.
 
diff --git a/packages/docs/docs/plugin/option-api.md b/packages/docs/docs/plugin/option-api.md
index 6be11d8cb9..a9764fd457 100644
--- a/packages/docs/docs/plugin/option-api.md
+++ b/packages/docs/docs/plugin/option-api.md
@@ -434,3 +434,29 @@ Then, VuePress will automatically inject these components behind the layout comp
 </div>
 </div>
 ```
+
+## registerCommand
+
+- Type: `function`
+- Default: `undefined`
+
+Register a extra command to enhance the CLI of vuepress. The function will be called with a [CAC](https://github.com/cacjs/cac)'s instance as the first argument.
+
+```js
+module.exports = {
+  registerCommand (cli) {
+    cli
+      .command('info [targetDir]', '')
+      .option('--debug', 'display info in debug mode')
+      .action((dir = '.') => {
+        console.log('Display info of your website')
+      })
+  }
+}
+```
+
+Now you can use `vuepress info [targetDir]` a in your project!
+
+::: tip
+Note that a custom command registered by a plugin requires VuePress to locate your site configuration like `vuepress dev` and `vuepress build`, so when developing a command, be sure to lead the user to pass `targetDir` as an CLI argument.
+:::
diff --git a/packages/docs/docs/zh/miscellaneous/design-concepts.md b/packages/docs/docs/zh/miscellaneous/design-concepts.md
index ea64376650..6adb30cb10 100644
--- a/packages/docs/docs/zh/miscellaneous/design-concepts.md
+++ b/packages/docs/docs/zh/miscellaneous/design-concepts.md
@@ -187,9 +187,8 @@ i18n UI 最终的路由将是 `/i18n/`.
 
 ## 其他
 
-本着解耦的目标，引入 monorepo 后，我们也得以将 VuePress 分离成以下几个库：
+本着解耦的目标，引入 monorepo 后，我们也得以将 VuePress 分离成以下两个库：
 
-- [@vuepress/cli](https://github.com/vuejs/vuepress/tree/master/packages/@vuepress/cli): 命令行指令的管理；
 - [@vuepress/core](https://github.com/vuejs/vuepress/tree/master/packages/@vuepress/core)：包含 dev、build 的核心实现和 Plugin API；
 - [@vuepress/theme-default](https://github.com/vuejs/vuepress/tree/master/packages/@vuepress/theme-default)：你现在所看到的默认主题。
 
diff --git a/packages/docs/docs/zh/plugin/option-api.md b/packages/docs/docs/zh/plugin/option-api.md
index 188ddaf363..1ed3a75dd6 100644
--- a/packages/docs/docs/zh/plugin/option-api.md
+++ b/packages/docs/docs/zh/plugin/option-api.md
@@ -436,3 +436,30 @@ VuePress 将会自动将这些组件注入到布局组件的隔壁：
 </div>
 </div>
 ```
+
+## registerCommand
+
+- 类型: `function`
+- 默认值: `undefined`
+
+注册一个额外的 command 来增强 vuepress 的 CLI。这个函数将会以一个 [CAC](https://github.com/cacjs/cac) 的实例作为第一个参数被调用。
+
+```js
+module.exports = {
+  registerCommand (cli) {
+    cli
+      .command('info [targetDir]', '')
+      .option('--debug', 'display info in debug mode')
+      .action((dir = '.') => {
+        console.log('Display info of your website')
+      })
+  }
+}
+```
+
+现在你可以在你项目中使用 `vuepress info [targetDir]` 了！
+
+::: tip
+值得注意的是，一个自定义的 command 需要 VuePress 像 `vuepress dev` 或 `vuepress build` 去定位到你的站点配置，所以在开发一个 command 时，请确保引导用户去传入 `targetDir` 作为 CLI 参数的一部分。
+:::
+

From 9d7e8d02605c8cf469c3b06b16c815197d2551cc Mon Sep 17 00:00:00 2001
From: ULIVZ <472590061@qq.com>
Date: Wed, 5 Dec 2018 02:30:01 +0800
Subject: [PATCH 06/10] chore: tweaks

---
 packages/@vuepress/core/lib/index.js          |  1 -
 packages/@vuepress/core/lib/unknownCommand.js | 11 -----------
 2 files changed, 12 deletions(-)
 delete mode 100644 packages/@vuepress/core/lib/unknownCommand.js

diff --git a/packages/@vuepress/core/lib/index.js b/packages/@vuepress/core/lib/index.js
index 522ff40069..43a6d0124b 100644
--- a/packages/@vuepress/core/lib/index.js
+++ b/packages/@vuepress/core/lib/index.js
@@ -3,4 +3,3 @@
 exports.dev = require('./dev')
 exports.build = require('./build')
 exports.eject = require('./eject')
-exports.unknownCommand = require('./unknownCommand')
diff --git a/packages/@vuepress/core/lib/unknownCommand.js b/packages/@vuepress/core/lib/unknownCommand.js
deleted file mode 100644
index 89c8cba18c..0000000000
--- a/packages/@vuepress/core/lib/unknownCommand.js
+++ /dev/null
@@ -1,11 +0,0 @@
-'use strict'
-
-module.exports = async function (commandName, sourceDir, cliOptions = {}) {
-  const prepare = require('./prepare/index')
-  const ctx = await prepare(sourceDir, cliOptions, false /* isProd */)
-  const cli = require('cac')()
-  cli.help()
-  ctx.pluginAPI.options.registerCommand.apply(cli)
-  cli.parse()
-  return cli
-}

From 7d3620c15bdd7b164e3f265d9d8f5f7db160c924 Mon Sep 17 00:00:00 2001
From: ULIVZ <472590061@qq.com>
Date: Wed, 5 Dec 2018 02:32:53 +0800
Subject: [PATCH 07/10] chore: modify the compatible node version to 8.6 or
 higher.

Since we have started to using `object spread properties` syntax

Ref: https://node.green/#ES2018-features-object-rest-spread-properties-object-spread-properties
---
 packages/@vuepress/core/package.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/@vuepress/core/package.json b/packages/@vuepress/core/package.json
index 7c6c510ce0..eada85823b 100644
--- a/packages/@vuepress/core/package.json
+++ b/packages/@vuepress/core/package.json
@@ -72,7 +72,7 @@
     "webpackbar": "^2.6.1"
   },
   "engines": {
-    "node": ">=8"
+    "node": ">=8.6"
   },
   "browserslist": [
     ">1%"

From 2ccec71be98717feaaacae905dcc3501613056ba Mon Sep 17 00:00:00 2001
From: ULIVZ <472590061@qq.com>
Date: Wed, 5 Dec 2018 02:35:19 +0800
Subject: [PATCH 08/10] chore: add missing deps

---
 packages/@vuepress/core/package.json | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/packages/@vuepress/core/package.json b/packages/@vuepress/core/package.json
index eada85823b..1b0fa4cacc 100644
--- a/packages/@vuepress/core/package.json
+++ b/packages/@vuepress/core/package.json
@@ -69,7 +69,9 @@
     "webpack-chain": "^4.6.0",
     "webpack-merge": "^4.1.2",
     "webpack-serve": "^1.0.2",
-    "webpackbar": "^2.6.1"
+    "webpackbar": "^2.6.1",
+    "semver": "^5.5.0",
+    "cac": "^6.3.3"
   },
   "engines": {
     "node": ">=8.6"

From 30b697fdee6ef4520145405cae628a0c6ebc3248 Mon Sep 17 00:00:00 2001
From: ULIVZ <472590061@qq.com>
Date: Thu, 6 Dec 2018 09:13:02 +0800
Subject: [PATCH 09/10] chore: bump version of CAC

---
 packages/@vuepress/core/package.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/@vuepress/core/package.json b/packages/@vuepress/core/package.json
index db56acf5e5..63400739d0 100644
--- a/packages/@vuepress/core/package.json
+++ b/packages/@vuepress/core/package.json
@@ -71,7 +71,7 @@
     "webpack-serve": "^1.0.2",
     "webpackbar": "^2.6.1",
     "semver": "^5.5.0",
-    "cac": "^6.3.3"
+    "cac": "^6.3.9"
   },
   "engines": {
     "node": ">=8.6"

From 1f7bf85bdd7e96e4f759d3785c96b60e32e5fa83 Mon Sep 17 00:00:00 2001
From: ULIVZ <472590061@qq.com>
Date: Sat, 8 Dec 2018 22:10:55 +0800
Subject: [PATCH 10/10] chore: rename 'registerCommand' to 'extendCli'

---
 packages/@vuepress/core/lib/plugin-api/constants.js | 2 +-
 packages/@vuepress/core/lib/plugin-api/index.js     | 4 ++--
 packages/vuepress/lib/handleUnknownCommand.js       | 4 ++--
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/packages/@vuepress/core/lib/plugin-api/constants.js b/packages/@vuepress/core/lib/plugin-api/constants.js
index e5193b99a7..883447930d 100644
--- a/packages/@vuepress/core/lib/plugin-api/constants.js
+++ b/packages/@vuepress/core/lib/plugin-api/constants.js
@@ -20,7 +20,7 @@ const PLUGIN_OPTION_META_MAP = {
   GLOBAL_UI_COMPONENTS: { name: 'globalUIComponents', types: [String, Array] },
   DEFINE: { name: 'define', types: [Function, Object] },
   ALIAS: { name: 'alias', types: [Function, Object] },
-  REGISTER_COMMAND: { name: 'registerCommand', types: [Function] }
+  EXTEND_CLI: { name: 'extendCli', types: [Function] }
 }
 
 const PLUGIN_OPTION_MAP = {}
diff --git a/packages/@vuepress/core/lib/plugin-api/index.js b/packages/@vuepress/core/lib/plugin-api/index.js
index c41e5fc153..c4aa89e4f9 100644
--- a/packages/@vuepress/core/lib/plugin-api/index.js
+++ b/packages/@vuepress/core/lib/plugin-api/index.js
@@ -207,7 +207,7 @@ module.exports = class PluginAPI {
     globalUIComponents,
     define,
     alias,
-    registerCommand
+    extendCli
   }) {
     const isInternalPlugin = pluginName.startsWith('@vuepress/internal-')
     logger[isInternalPlugin ? 'debug' : 'tip'](pluginLog(pluginName, shortcut))
@@ -230,7 +230,7 @@ module.exports = class PluginAPI {
       .registerOption(PLUGIN_OPTION_MAP.GLOBAL_UI_COMPONENTS.key, globalUIComponents, pluginName)
       .registerOption(PLUGIN_OPTION_MAP.DEFINE.key, define, pluginName)
       .registerOption(PLUGIN_OPTION_MAP.ALIAS.key, alias, pluginName)
-      .registerOption(PLUGIN_OPTION_MAP.REGISTER_COMMAND.key, registerCommand, pluginName)
+      .registerOption(PLUGIN_OPTION_MAP.EXTEND_CLI.key, extendCli, pluginName)
   }
 }
 
diff --git a/packages/vuepress/lib/handleUnknownCommand.js b/packages/vuepress/lib/handleUnknownCommand.js
index 0394e9bf4a..cc20a2aed7 100644
--- a/packages/vuepress/lib/handleUnknownCommand.js
+++ b/packages/vuepress/lib/handleUnknownCommand.js
@@ -39,7 +39,7 @@ module.exports = async function (cli, options) {
 
     if (sourceDir) {
       context = await prepare(sourceDir, options)
-      context.pluginAPI.options.registerCommand.apply(cli)
+      context.pluginAPI.options.extendCli.apply(cli)
     }
 
     logger.setOptions({ logLevel: 3 })
@@ -107,7 +107,7 @@ function registerUnknownCommands (cli, options) {
           ...options,
           ...commandoptions
         }, false /* isProd */)
-        await context.pluginAPI.options.registerCommand.apply(subCli)
+        await context.pluginAPI.options.extendCli.apply(subCli)
       },
       async afterParse (subCli) {
         if (!subCli.matchedCommand) {