diff --git a/.gitignore b/.gitignore
index 35884956f..7e95d3c2b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -11,3 +11,6 @@ npm-debug.log
 /.settings
 /.idea
 /.vscode
+
+# coverage
+coverage
diff --git a/README.md b/README.md
index 18323c175..cf17b76c2 100644
--- a/README.md
+++ b/README.md
@@ -96,6 +96,40 @@ As long as your git commit messages are conventional and accurate, you no longer
 
 After you cut a release, you can push the new git tag and `npm publish` (or `npm publish --tag next`) when you're ready.
 
+### Release as a pre-release
+
+Use `--prerelease`, you can generate a pre-release.
+
+Suppose the last version of your code is `1.0.0`, and your code to be committed has patched changes. Run
+```bash
+# npm run script
+npm run release -- --prerelease
+```
+you will get version `1.0.1-0`.
+
+If you want to name the pre-release, you specify the name via `--prerelease <name>`.
+
+For example, the wanted name is `alpha`
+. Use the example above:
+```bash
+# npm run script
+npm run release -- --prerelease alpha
+```
+you will get version `1.0.1-alpha.0`
+
+### Release as a target type imperatively like `npm version`
+
+You can use `--release-as` to generate a `major`, `minor` or `patch` release imperatively.
+
+Suppose the last version of your code is `1.0.0`, and your code to be committed has patched changes. Run
+```bash
+# npm run script
+npm run release -- --release-as minor
+```
+you will get version `1.1.0` rather than the smartly generated version `1.0.1`.
+
+**NOTE:** you can combine `--release-as` and `--prerelease` to generate a release. That's useful when publishing experimental feature(s).
+
 ### Prevent Git Hooks
 
 If you use git hooks, like pre-commit, to test your code before committing, you can prevent hooks from being verified during the commit step by passing the `--no-verify` option:
diff --git a/bin/cli.js b/bin/cli.js
new file mode 100755
index 000000000..c80a2e129
--- /dev/null
+++ b/bin/cli.js
@@ -0,0 +1,9 @@
+#!/usr/bin/env node
+var standardVersion = require('../index')
+var cmdParser = require('../command')
+
+standardVersion(cmdParser.argv, function (err) {
+  if (err) {
+    process.exit(1)
+  }
+})
diff --git a/cli.js b/command.js
similarity index 75%
rename from cli.js
rename to command.js
index f1cbe3088..e6fcdd443 100755
--- a/cli.js
+++ b/command.js
@@ -1,9 +1,21 @@
-#!/usr/bin/env node
-var standardVersion = require('./index')
 var defaults = require('./defaults')
 
-var argv = require('yargs')
+module.exports = require('yargs')
   .usage('Usage: $0 [options]')
+  .option('release-as', {
+    alias: 'r',
+    describe: 'Specify the release type manually. like npm version xxx with limited choices',
+    requiresArg: true,
+    string: true,
+    choices: ['major', 'minor', 'patch'],
+    global: true
+  })
+  .option('prerelease', {
+    alias: 'p',
+    describe: 'make a pre-release with optional option value to specify a tag id',
+    string: true,
+    global: true
+  })
   .option('infile', {
     alias: 'i',
     describe: 'Read the CHANGELOG from this file',
@@ -51,15 +63,10 @@ var argv = require('yargs')
     default: defaults.silent,
     global: true
   })
+  .version()
+  .alias('version', 'v')
   .help()
   .alias('help', 'h')
   .example('$0', 'Update changelog and tag release')
   .example('$0 -m "%s: see changelog for details"', 'Update changelog and tag release with custom commit message')
   .wrap(97)
-  .argv
-
-standardVersion(argv, function (err) {
-  if (err) {
-    process.exit(1)
-  }
-})
diff --git a/index.js b/index.js
index 1b57b7837..a619c9ccb 100755
--- a/index.js
+++ b/index.js
@@ -16,40 +16,121 @@ module.exports = function standardVersion (argv, done) {
   var pkg = require(pkgPath)
   var defaults = require('./defaults')
 
-  argv = objectAssign(defaults, argv)
+  var args = objectAssign({}, defaults, argv)
 
-  conventionalRecommendedBump({
-    preset: 'angular'
-  }, function (err, release) {
+  bumpVersion(args.releaseAs, function (err, release) {
     if (err) {
-      printError(argv, err.message)
+      printError(args, err.message)
       return done(err)
     }
 
     var newVersion = pkg.version
-    if (!argv.firstRelease) {
-      newVersion = semver.inc(pkg.version, release.releaseType)
-      checkpoint(argv, 'bumping version in package.json from %s to %s', [pkg.version, newVersion])
+
+    if (!args.firstRelease) {
+      var releaseType = getReleaseType(args.prerelease, release.releaseType, pkg.version)
+      newVersion = semver.inc(pkg.version, releaseType, args.prerelease)
+
+      checkpoint(args, 'bumping version in package.json from %s to %s', [pkg.version, newVersion])
+
       pkg.version = newVersion
       fs.writeFileSync(pkgPath, JSON.stringify(pkg, null, 2) + '\n', 'utf-8')
     } else {
-      checkpoint(argv, 'skip version bump on first release', [], chalk.red(figures.cross))
+      checkpoint(args, 'skip version bump on first release', [], chalk.red(figures.cross))
     }
 
-    outputChangelog(argv, function (err) {
+    outputChangelog(args, function (err) {
       if (err) {
         return done(err)
       }
-      commit(argv, newVersion, function (err) {
+      commit(args, newVersion, function (err) {
         if (err) {
           return done(err)
         }
-        return tag(newVersion, pkg.private, argv, done)
+        return tag(newVersion, pkg.private, args, done)
       })
     })
   })
 }
 
+function getReleaseType (prerelease, expectedReleaseType, currentVersion) {
+  if (isString(prerelease)) {
+    if (isInPrerelease(currentVersion)) {
+      if (shouldContinuePrerelease(currentVersion, expectedReleaseType) ||
+        getTypePriority(getCurrentActiveType(currentVersion)) > getTypePriority(expectedReleaseType)
+      ) {
+        return 'prerelease'
+      }
+    }
+
+    return 'pre' + expectedReleaseType
+  } else {
+    return expectedReleaseType
+  }
+}
+
+function isString (val) {
+  return typeof val === 'string'
+}
+
+/**
+ * if a version is currently in pre-release state,
+ * and if it current in-pre-release type is same as expect type,
+ * it should continue the pre-release with the same type
+ *
+ * @param version
+ * @param expectType
+ * @return {boolean}
+ */
+function shouldContinuePrerelease (version, expectType) {
+  return getCurrentActiveType(version) === expectType
+}
+
+function isInPrerelease (version) {
+  return Array.isArray(semver.prerelease(version))
+}
+
+var TypeList = ['major', 'minor', 'patch'].reverse()
+
+/**
+ * extract the in-pre-release type in target version
+ *
+ * @param version
+ * @return {string}
+ */
+function getCurrentActiveType (version) {
+  var typelist = TypeList
+  for (var i = 0; i < typelist.length; i++) {
+    if (semver[typelist[i]](version)) {
+      return typelist[i]
+    }
+  }
+}
+
+/**
+ * calculate the priority of release type,
+ * major - 2, minor - 1, patch - 0
+ *
+ * @param type
+ * @return {number}
+ */
+function getTypePriority (type) {
+  return TypeList.indexOf(type)
+}
+
+function bumpVersion (releaseAs, callback) {
+  if (releaseAs) {
+    callback(null, {
+      releaseType: releaseAs
+    })
+  } else {
+    conventionalRecommendedBump({
+      preset: 'angular'
+    }, function (err, release) {
+      callback(err, release)
+    })
+  }
+}
+
 function outputChangelog (argv, cb) {
   createIfMissing(argv)
   var header = '# Change Log\n\nAll notable changes to this project will be documented in this file. See [standard-version](https://github.com/conventional-changelog/standard-version) for commit guidelines.\n'
diff --git a/package.json b/package.json
index 66462cb2b..626133b45 100644
--- a/package.json
+++ b/package.json
@@ -2,12 +2,12 @@
   "name": "standard-version",
   "version": "3.0.0",
   "description": "replacement for `npm version` with automatic CHANGELOG generation",
-  "bin": "cli.js",
+  "bin": "bin/cli.js",
   "scripts": {
     "pretest": "standard",
     "coverage": "nyc report --reporter=text-lcov | coveralls",
     "test": "nyc mocha --timeout=20000 test.js",
-    "release": "./cli.js"
+    "release": "bin/cli.js"
   },
   "repository": {
     "type": "git",
@@ -43,6 +43,7 @@
     "yargs": "^6.0.0"
   },
   "devDependencies": {
+    "bluebird": "^3.4.6",
     "chai": "^3.5.0",
     "coveralls": "^2.11.9",
     "mocha": "^3.1.0",
diff --git a/test.js b/test.js
index 51a72205b..f7cb8cd76 100644
--- a/test.js
+++ b/test.js
@@ -9,10 +9,14 @@ var path = require('path')
 var stream = require('stream')
 var mockGit = require('mock-git')
 var mockery = require('mockery')
+var semver = require('semver')
+var Promise = require('bluebird')
+var cli = require('./command')
+var standardVersion = require('./index')
 
 var should = require('chai').should()
 
-var cliPath = path.resolve(__dirname, './cli.js')
+var cliPath = path.resolve(__dirname, './bin/cli.js')
 
 function branch (branch) {
   shell.exec('git branch ' + branch)
@@ -34,10 +38,15 @@ function execCli (argString) {
   return shell.exec('node ' + cliPath + (argString != null ? ' ' + argString : ''))
 }
 
+function execCliAsync (argString) {
+  return Promise.promisify(standardVersion)(cli.parse('standard-version ' + argString + ' --silent'))
+}
+
 function writePackageJson (version, option) {
   option = option || {}
   var pkg = objectAssign(option, {version: version})
   fs.writeFileSync('package.json', JSON.stringify(pkg), 'utf-8')
+  delete require.cache[require.resolve(path.join(process.cwd(), 'package.json'))]
 }
 
 function writeGitPreCommitHook () {
@@ -60,6 +69,10 @@ function finishTemp () {
   shell.rm('-rf', 'tmp')
 }
 
+function getPackageVersion () {
+  return JSON.parse(fs.readFileSync('package.json', 'utf-8')).version
+}
+
 describe('cli', function () {
   beforeEach(initInTempFolder)
   afterEach(finishTemp)
@@ -119,9 +132,9 @@ describe('cli', function () {
       execCli('--commit-all').code.should.equal(0)
 
       var content = fs.readFileSync('CHANGELOG.md', 'utf-8')
-      var status = shell.exec('git status')
+      var status = shell.exec('git status --porcelain') // see http://unix.stackexchange.com/questions/155046/determine-if-git-working-directory-is-clean-from-a-script
 
-      status.should.match(/On branch master\nnothing to commit, working (directory|tree) clean\n/)
+      status.should.equal('')
       status.should.not.match(/STUFF.md/)
 
       content.should.match(/1\.0\.1/)
@@ -197,6 +210,126 @@ describe('cli', function () {
     })
   })
 
+  describe('pre-release', function () {
+    it('works fine without specifying a tag id when prereleasing', function () {
+      writePackageJson('1.0.0')
+      fs.writeFileSync('CHANGELOG.md', 'legacy header format<a name="1.0.0">\n', 'utf-8')
+
+      commit('feat: first commit')
+      return execCliAsync('--prerelease')
+        .then(function () {
+          // it's a feature commit, so it's minor type
+          getPackageVersion().should.equal('1.1.0-0')
+        })
+    })
+  })
+
+  describe('manual-release', function () {
+    it('throws error when not specifying a release type', function () {
+      writePackageJson('1.0.0')
+      fs.writeFileSync('CHANGELOG.md', 'legacy header format<a name="1.0.0">\n', 'utf-8')
+
+      commit('fix: first commit')
+      execCli('--release-as').code.should.above(0)
+    })
+
+    describe('release-types', function () {
+      var regularTypes = ['major', 'minor', 'patch']
+
+      regularTypes.forEach(function (type) {
+        it('creates a ' + type + ' release', function () {
+          var originVer = '1.0.0'
+          writePackageJson(originVer)
+          fs.writeFileSync('CHANGELOG.md', 'legacy header format<a name="1.0.0">\n', 'utf-8')
+
+          commit('fix: first commit')
+
+          return execCliAsync('--release-as ' + type)
+            .then(function () {
+              var version = {
+                major: semver.major(originVer),
+                minor: semver.minor(originVer),
+                patch: semver.patch(originVer)
+              }
+
+              version[type] += 1
+
+              getPackageVersion().should.equal(version.major + '.' + version.minor + '.' + version.patch)
+            })
+        })
+      })
+
+      // this is for pre-releases
+      regularTypes.forEach(function (type) {
+        it('creates a pre' + type + ' release', function () {
+          var originVer = '1.0.0'
+          writePackageJson(originVer)
+          fs.writeFileSync('CHANGELOG.md', 'legacy header format<a name="1.0.0">\n', 'utf-8')
+
+          commit('fix: first commit')
+
+          return execCliAsync('--release-as ' + type + ' --prerelease ' + type)
+            .then(function () {
+              var version = {
+                major: semver.major(originVer),
+                minor: semver.minor(originVer),
+                patch: semver.patch(originVer)
+              }
+
+              version[type] += 1
+
+              getPackageVersion().should.equal(version.major + '.' + version.minor + '.' + version.patch + '-' + type + '.0')
+            })
+        })
+      })
+    })
+
+    it('creates a prerelease with a new minor version after two prerelease patches', function () {
+      writePackageJson('1.0.0')
+      fs.writeFileSync('CHANGELOG.md', 'legacy header format<a name="1.0.0">\n', 'utf-8')
+
+      commit('fix: first patch')
+      return execCliAsync('--release-as patch --prerelease dev')
+        .then(function () {
+          getPackageVersion().should.equal('1.0.1-dev.0')
+        })
+
+        // second
+        .then(function () {
+          commit('fix: second patch')
+          return execCliAsync('--prerelease dev')
+        })
+        .then(function () {
+          getPackageVersion().should.equal('1.0.1-dev.1')
+        })
+
+        // third
+        .then(function () {
+          commit('feat: first new feat')
+          return execCliAsync('--release-as minor --prerelease dev')
+        })
+        .then(function () {
+          getPackageVersion().should.equal('1.1.0-dev.0')
+        })
+
+        .then(function () {
+          commit('fix: third patch')
+          return execCliAsync('--release-as minor --prerelease dev')
+        })
+        .then(function () {
+          getPackageVersion().should.equal('1.1.0-dev.1')
+        })
+
+        .then(function () {
+          commit('fix: forth patch')
+          return execCliAsync('--prerelease dev')
+        })
+        .then(function () {
+          getPackageVersion().should.equal('1.1.0-dev.2')
+        })
+    })
+  })
+
   it('handles commit messages longer than 80 characters', function () {
     commit('feat: first commit')
     shell.exec('git tag -a v1.0.0 -m "my awesome first release"')