diff --git a/.gitignore b/.gitignore
index b32672d..a6f192e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,3 +15,4 @@ node_modules
 npm-debug.log
 samples
 tmp_samples
+!test/fixtures/*.log
diff --git a/README.md b/README.md
index 1e70dec..2b341e4 100644
--- a/README.md
+++ b/README.md
@@ -180,6 +180,8 @@ This is useful CI environments where you want to check if your docs are up to da
 
 You can print to stdout by using the `-s` or `--stdout` option.
 
+This option is only applicable when specifying a single filename which doctoc is to run on. If you are specifying a folder or multiple files, the dry run option should be used instead.
+
 ### Only update existing ToC
 
 Use `--update-only` or `-u` to only update the existing ToC. That is, the Markdown files without ToC will be left untouched. It is good if you want to use `doctoc` with `lint-staged`.
diff --git a/doctoc.js b/doctoc.js
index d5247ec..50930c3 100755
--- a/doctoc.js
+++ b/doctoc.js
@@ -112,7 +112,7 @@ var title = argv.t || argv.title;
 var notitle = argv.T || argv.notitle;
 var entryPrefix = argv.entryprefix || '-';
 var processAll = argv.all;
-var stdOut = argv.s || argv.stdout
+var stdOut = argv.s || argv.stdout || false;
 var updateOnly = argv.u || argv['update-only']
 var dryRun = argv.d || argv.dryrun || false;
 
@@ -125,10 +125,21 @@ else if (minHeaderLevel && minHeaderLevel > 2) { console.error('Min. heading lev
 
 if (maxHeaderLevel && maxHeaderLevel < minHeaderLevel) { console.error('Max. heading level: ' + maxHeaderLevel + ' is less than the defined Min. heading level: ' + minHeaderLevel), printUsageAndExit(true); }
 
+if (argv._.length > 1 && stdOut) {
+  console.error('--stdout cannot be used with multiple files/directories. Use --dryrun instead.');
+  process.exitCode = 2;
+  return;
+}
 
 for (var i = 0; i < argv._.length; i++) {
   var target = cleanPath(argv._[i])
-    , stat = fs.statSync(target)
+    , stat = fs.statSync(target);
+
+  if (stat.isDirectory() && stdOut) {
+    console.error('--stdout cannot be used with multiple files/directories. Use --dryrun instead.');
+    process.exitCode = 2;
+    return;
+  }
 
   if (stat.isDirectory()) {
     console.log ('\nDocToccing "%s" and its sub directories for %s.', target, mode);
diff --git a/test/fixtures/invalid_stdout/readme.md b/test/fixtures/invalid_stdout/readme.md
new file mode 100644
index 0000000..2534d7f
--- /dev/null
+++ b/test/fixtures/invalid_stdout/readme.md
@@ -0,0 +1,18 @@
+# Hello, world!
+
+README to test doctoc with user-specified titles.
+
+<!-- START doctoc generated TOC please keep comment here to allow auto update -->
+<!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE -->
+## Table of Contents
+
+- [Installation](#installation)
+- [API](#api)
+- [License](#license)
+
+<!-- END doctoc generated TOC please keep comment here to allow auto update -->
+
+
+## Installation
+## API
+## License
diff --git a/test/fixtures/stdout.md b/test/fixtures/stdout.log
similarity index 100%
rename from test/fixtures/stdout.md
rename to test/fixtures/stdout.log
diff --git a/test/fixtures/stdout_run_on_directory.log b/test/fixtures/stdout_run_on_directory.log
new file mode 100644
index 0000000..c0681dd
--- /dev/null
+++ b/test/fixtures/stdout_run_on_directory.log
@@ -0,0 +1,11 @@
+StdOut cannot be used on a directory. Using dryrun instead.
+
+DocToccing "test/fixtures/invalid_stdout" and its sub directories for github.com.
+
+Found readme.md in "test/fixtures/invalid_stdout"
+
+==================
+
+"test/fixtures/invalid_stdout/readme.md" is up to date
+
+Everything is OK.
diff --git a/test/transform-stdout.js b/test/transform-stdout.js
index 85b4455..74a7df2 100644
--- a/test/transform-stdout.js
+++ b/test/transform-stdout.js
@@ -13,7 +13,7 @@ test('\nshould print to stdout with --stdout option', function (t) {
         return;
       }
       t.deepEqual(stdout
-        , fs.readFileSync(__dirname + '/fixtures/stdout.md', 'utf8')
+        , fs.readFileSync(__dirname + '/fixtures/stdout.log', 'utf8')
         , 'spits out the correct table of contents')
 
       t.end()
@@ -28,9 +28,22 @@ test('\nshould print to stdout with -s option', function (t) {
         return;
       }
       t.deepEqual(stdout
-        , fs.readFileSync(__dirname + '/fixtures/stdout.md', 'utf8')
+        , fs.readFileSync(__dirname + '/fixtures/stdout.log', 'utf8')
         , 'spits out the correct table of contents')
 
       t.end()
     })
 })
+
+test('\nshould exit with error code as --stdout option is not supported on a directory', function (t) {
+
+    exec('node doctoc.js test/fixtures/invalid_stdout --stdout', function (error, stdout, stderr) {
+      if (error) {
+        t.deepEqual(error.code, 2, 'process exited with error code 2 as expected');
+        t.end();
+      } else {
+        t.fail('process did not produce an error: ' + error);
+        t.end();
+      }
+    })
+})