diff --git a/cli.mjs b/cli.mjs
index 53aff84..f7dd5ac 100644
--- a/cli.mjs
+++ b/cli.mjs
@@ -27,6 +27,7 @@ function PrintHelp() {
   console.log('eltro test/mytest.mjs')
   console.log('eltro dot test/*.mjs')
   console.log('eltro -r dot test/**/*.test.mjs')
+  console.log('')
   process.exit(1)
 }
 
diff --git a/lib/cli.mjs b/lib/cli.mjs
index 97051b7..2455c2c 100644
--- a/lib/cli.mjs
+++ b/lib/cli.mjs
@@ -28,6 +28,9 @@ CLI.prototype.parseOptions = function(args) {
       }
       this.reporter = args[i + 1]
       i++
+    } else if (args[i][0] === '-') {
+      this.errored = true
+      return
     } else {
       this.targets.push(args[i])
     }
diff --git a/test/cli.test.mjs b/test/cli.test.mjs
index 0df2ec9..582740e 100644
--- a/test/cli.test.mjs
+++ b/test/cli.test.mjs
@@ -72,6 +72,16 @@ e.describe('CLI', function() {
       assert.deepEqual(cli.targets, ['test/**'])
       assert.notOk(cli.errored)
     })
+
+    e.test('should mark errored if invalid shorthand option', function() {
+      cli.parseOptions(['-A'])
+      assert.ok(cli.errored)
+    })
+
+    e.test('should mark errored if invalid longhand option', function() {
+      cli.parseOptions(['--asdf'])
+      assert.ok(cli.errored)
+    })
   })
 
   /*****************************************