diff --git a/lib/invoker.js b/lib/invoker.js
index b185fe7..61fe699 100644
--- a/lib/invoker.js
+++ b/lib/invoker.js
@@ -19,18 +19,28 @@ class Invoker {
       this.showVersion()
       process.exit(0)
     }
+    if (files.length === 0 && !this.options.stdin) {
+      // nothing to do...
+      this.showHelp()
+      process.exit(0)
+    }
     Invoker.prepareProcessor(args, asciidoctor)
     const options = this.options.options
     const failureLevel = options['failure_level']
-    if (this.options.stdin) {
-      await Invoker.convertFromStdin(options, args)
-      Invoker.exit(failureLevel)
-    } else if (files && files.length > 0) {
-      Invoker.processFiles(files, verbose, args['timings'], options)
+    try {
+      if (this.options.stdin) {
+        await Invoker.convertFromStdin(options, args)
+      } else if (files && files.length > 0) {
+        Invoker.convertFiles(files, verbose, args['timings'], options)
+      }
       Invoker.exit(failureLevel)
-    } else {
-      this.showHelp()
-      process.exit(0)
+    } catch (e) {
+      if (e && e.name === 'NotImplementedError' && e.message === `asciidoctor: FAILED: missing converter for backend '${options.backend}'. Processing aborted.`) {
+        console.error(`> Error: missing converter for backend '${options.backend}'. Processing aborted.`)
+        console.error(`> You might want to require a Node.js package with --require option to support this backend.`)
+        process.exit(1)
+      }
+      throw e
     }
   }
 
@@ -69,31 +79,14 @@ CLI version ${pkg.version}`
     if (args['timings']) {
       const timings = asciidoctor.Timings.create()
       const instanceOptions = Object.assign({}, options, { timings })
-      Invoker.convert(asciidoctor.convert, data, instanceOptions)
+      asciidoctor.convert(data, instanceOptions)
       timings.printReport(process.stderr, '-')
     } else {
-      Invoker.convert(asciidoctor.convert, data, options)
-    }
-  }
-
-  static convert (processorFn, input, options) {
-    try {
-      processorFn.apply(asciidoctor, [input, options])
-    } catch (e) {
-      if (e && e.name === 'NotImplementedError' && e.message === `asciidoctor: FAILED: missing converter for backend '${options.backend}'. Processing aborted.`) {
-        console.error(`> Error: missing converter for backend '${options.backend}'. Processing aborted.`)
-        console.error(`> You might want to require a Node.js package with --require option to support this backend.`)
-        process.exit(1)
-      }
-      throw e
+      asciidoctor.convert(data, options)
     }
   }
 
-  static convertFile (file, options) {
-    Invoker.convert(asciidoctor.convertFile, file, options)
-  }
-
-  static processFiles (files, verbose, timings, options) {
+  static convertFiles (files, verbose, timings, options) {
     files.forEach((file) => {
       if (verbose) {
         console.log(`converting file ${file}`)
@@ -101,10 +94,10 @@ CLI version ${pkg.version}`
       if (timings) {
         const timings = asciidoctor.Timings.create()
         const instanceOptions = Object.assign({}, options, { timings })
-        Invoker.convertFile(file, instanceOptions)
+        asciidoctor.convertFile(file, instanceOptions)
         timings.printReport(process.stderr, file)
       } else {
-        Invoker.convertFile(file, options)
+        asciidoctor.convertFile(file, options)
       }
     })
   }
diff --git a/test/test.js b/test/test.js
index d6b4275..028328c 100644
--- a/test/test.js
+++ b/test/test.js
@@ -156,6 +156,7 @@ describe('Help', () => {
 describe('Print timings report', () => {
   it('should print timings report', () => {
     sinon.stub(process.stderr, 'write')
+    sinon.stub(process.stdout, 'write')
     sinon.stub(process, 'exit')
     try {
       new Invoker(new Options().parse(['node', 'asciidoctor', `${__dirname}/fixtures/sample.adoc`, '--timings', '-o', '-'])).invoke()
@@ -166,6 +167,43 @@ describe('Print timings report', () => {
       expect(process.stderr.write.getCall(3).args[0]).to.include('Total time (read, parse and convert):')
     } finally {
       process.stderr.write.restore()
+      process.stdout.write.restore()
+      process.exit.restore()
+    }
+  })
+})
+
+describe('Write to stdout', () => {
+  it('should write to stdout', () => {
+    sinon.stub(process.stdout, 'write')
+    sinon.stub(process, 'exit')
+    try {
+      new Invoker(new Options().parse(['node', 'asciidoctor', `${__dirname}/fixtures/sample.adoc`, '-a', 'nofooter', '-o', '-'])).invoke()
+      expect(process.stdout.write.called).to.be.true()
+      expect(process.stdout.write.getCall(0).args[0]).to.include(`<body class="article">
+<div id="header">
+<h1>Title</h1>
+</div>
+<div id="content">
+<div id="preamble">
+<div class="sectionbody">
+<div class="paragraph">
+<p>This is a sample document</p>
+</div>
+</div>
+</div>
+<div class="sect1">
+<h2 id="_first_section">First section</h2>
+<div class="sectionbody">
+<div class="paragraph">
+<p>This is a paragraph.</p>
+</div>
+</div>
+</div>
+</div>
+</body>`)
+    } finally {
+      process.stdout.write.restore()
       process.exit.restore()
     }
   })
@@ -227,7 +265,7 @@ describe('Process files', () => {
   it('should exit with code 1 when failure level is lower than the maximum logging level', () => {
     sinon.stub(process, 'exit')
     try {
-      Invoker.processFiles([bookFilePath], false, false)
+      Invoker.convertFiles([bookFilePath], false, false)
       Invoker.exit(3) // ERROR: 3
       expect(process.exit.called).to.be.true()
       expect(process.exit.calledWith(1)).to.be.true()
@@ -239,7 +277,7 @@ describe('Process files', () => {
   it('should exit with code 0 when failure level is lower than the maximum logging level', () => {
     sinon.stub(process, 'exit')
     try {
-      Invoker.processFiles([bookFilePath], false, false)
+      Invoker.convertFiles([bookFilePath], false, false)
       Invoker.exit(4) // FATAL: 4
       expect(process.exit.called).to.be.true()
       expect(process.exit.calledWith(0)).to.be.true()