diff --git a/script/texdoclib-cli.tlu b/script/texdoclib-cli.tlu
index b5a98bf..79c2026 100644
--- a/script/texdoclib-cli.tlu
+++ b/script/texdoclib-cli.tlu
@@ -106,14 +106,14 @@ local function parse_options()
         end
 
         for i, o in ipairs(C.options) do
-            if k == o["short"] or k == o["long"] then
+            if k == o['short'] or k == o['long'] then
                 k = i
                 break
             end
         end
 
         option = C.options[k]
-        if option['group'] == 'action' then
+        if option ~= nil and option['group'] == 'action' then
             if option['long'] == 'just-view' then
                 return true, 'view', cl_config
             elseif option['long'] == 'print-completion' then
@@ -121,7 +121,7 @@ local function parse_options()
             else
                 return true, option['long'], cl_config
             end
-        elseif option['group'] then
+        elseif option~=nil and option['group'] then
             if option['type'] == 'boolean' then
                 option['action'](cl_config, curr_arg)
             elseif option['type'] == 'string' then
diff --git a/spec/misc/errors_spec.rb b/spec/misc/errors_spec.rb
index afe8d44..3a8591c 100644
--- a/spec/misc/errors_spec.rb
+++ b/spec/misc/errors_spec.rb
@@ -3,34 +3,6 @@
 RSpec.describe "Errors", :type => :aruba do
   include_context "messages"
 
-  context "running without any option nor argument" do
-    before(:each) { run_texdoc }
-
-    it 'should result in the "no action" error' do
-      expect(last_command_started).to have_exit_status(2)
-      expect(stderr).to include(error_line "No action specified.")
-      expect(stderr).to include(error_line msg_usage)
-    end
-  end
-
-  context "missing arguments for Option -d" do
-    before(:each) { run_texdoc "-d" }
-
-    it 'should result in a getopt parser error' do
-      expect(last_command_started).to have_exit_status(1)
-      expect(stderr).to include(error_line "Option -d requires an argument.")
-    end
-  end
-
-  context "missing arguments for Option -c" do
-    before(:each) { run_texdoc "-c" }
-
-    it 'should result in a getopt parser error' do
-      expect(last_command_started).to have_exit_status(1)
-      expect(stderr).to include(error_line "Option -c requires an argument.")
-    end
-  end
-
   context "when any document for input cannot be found" do
     let(:nonexist_pkg) { "never_never_existing_package_foooooooooo" }
 
diff --git a/spec/misc/getopt_spec.rb b/spec/misc/getopt_spec.rb
index 02b4e30..83a6b7e 100644
--- a/spec/misc/getopt_spec.rb
+++ b/spec/misc/getopt_spec.rb
@@ -110,4 +110,42 @@
         debug_line "search", "Searching documents for pattern \"-texlive-en\"")
     end
   end
+
+  # error cases
+  context "running without any option nor argument" do
+    before(:each) { run_texdoc }
+
+    it 'should result in the "no action" error' do
+      expect(last_command_started).to have_exit_status(2)
+      expect(stderr).to include(error_line "No action specified.")
+      expect(stderr).to include(error_line msg_usage)
+    end
+  end
+
+  context "missing arguments for Option -d" do
+    before(:each) { run_texdoc "-d" }
+
+    it "should result in a getopt parser error" do
+      expect(last_command_started).to have_exit_status(1)
+      expect(stderr).to include(error_line "Option -d requires an argument.")
+    end
+  end
+
+  context "missing arguments for Option -c" do
+    before(:each) { run_texdoc "-c" }
+
+    it "should result in a getopt parser error" do
+      expect(last_command_started).to have_exit_status(1)
+      expect(stderr).to include(error_line "Option -c requires an argument.")
+    end
+  end
+
+  context "given an unknown option" do
+    before(:each) { run_texdoc "-x" }
+
+    it "should result in a getopt parser error" do
+      expect(last_command_started).to have_exit_status(2)
+      expect(stderr).to include(error_line "unknown option: -x")
+    end
+  end
 end