diff --git a/lib/rubyshell.rb b/lib/rubyshell.rb
index fc30d06..c97ade9 100644
--- a/lib/rubyshell.rb
+++ b/lib/rubyshell.rb
@@ -27,7 +27,7 @@ def debug=(value)
     def debug(value = true) # rubocop:disable Style/OptionalBooleanParameter
       previous_value = @debug_mode
 
-      @debug_mode = value
+      @debug_mode = value.nil? ? @debug_mode : value
 
       result = yield
 
diff --git a/spec/debugger_spec.rb b/spec/debugger_spec.rb
index 44633c7..900f202 100644
--- a/spec/debugger_spec.rb
+++ b/spec/debugger_spec.rb
@@ -7,154 +7,100 @@
     end
   end
 
-  describe ".run_wrapper" do
-    let(:log_output) { [] }
-    let(:logger) { double("Logger", info: nil) }
-
-    before do
-      allow(logger).to receive(:info) { |msg| log_output << msg }
-      allow(RubyShell).to receive(:logger).and_return(logger)
+  RSpec.shared_examples "a logged command" do |expected_output|
+    it "returns the command output" do
+      expect(subject_method).to eq(expected_output)
     end
 
-    after do
-      RubyShell.debug = false
+    it "logs the command executed" do
+      subject_method
+
+      expect(log_output.join).to include("Executed: echo #{expected_output}")
     end
 
-    context "when debug mode is disabled" do
-      def subject_method
-        sh.echo("hello")
-      end
+    it "logs the duration" do
+      subject_method
 
-      it "returns the command output" do
-        expect(subject_method).to eq("hello")
-      end
+      expect(log_output.join).to match(/Duration: \d+\.\d+s/)
+    end
 
-      it "does not log anything" do
-        subject_method
+    it "logs the pid" do
+      subject_method
 
-        expect(log_output).to be_empty
-      end
+      expect(log_output.join).to match(/Pid: \d+/)
     end
 
-    context "when debug mode is enabled via block" do
-      def subject_method
-        sh(debug: true) { echo("hello") }
-      end
+    it "logs the exit code" do
+      subject_method
 
-      it "returns the command output" do
-        expect(subject_method).to eq("hello")
-      end
+      expect(log_output.join).to include("Exit code: 0")
+    end
 
-      it "logs the command executed" do
-        subject_method
+    it "logs the stdout" do
+      subject_method
 
-        expect(log_output.join).to include("Executed: echo hello")
-      end
+      expect(log_output.join).to include("Stdout: \"#{expected_output}\"")
+    end
+  end
 
-      it "logs the duration" do
-        subject_method
+  RSpec.shared_examples "a silent command" do
+    it "returns the command output" do
+      expect(subject_method).to eq("hello")
+    end
 
-        expect(log_output.join).to match(/Duration: \d+\.\d+s/)
-      end
+    it "does not log anything" do
+      subject_method
+      expect(log_output).to be_empty
+    end
+  end
 
-      it "logs the pid" do
-        subject_method
+  describe ".run_wrapper" do
+    let(:log_output) { [] }
+    let(:logger) { double("Logger", info: nil) }
 
-        expect(log_output.join).to match(/Pid: \d+/)
-      end
+    before do
+      allow(logger).to receive(:info) { |msg| log_output << msg }
+      allow(RubyShell).to receive(:logger).and_return(logger)
+    end
 
-      it "logs the exit code" do
-        subject_method
+    after { RubyShell.debug = false }
 
-        expect(log_output.join).to include("Exit code: 0")
+    context "when debug mode is disabled" do
+      def subject_method
+        sh.echo("hello")
       end
+      it_behaves_like "a silent command"
+    end
 
-      it "logs the stdout" do
-        subject_method
-
-        expect(log_output.join).to include('Stdout: "hello"')
+    context "when debug mode is enabled via block" do
+      def subject_method
+        sh(debug: true) { echo("hello") }
       end
+      it_behaves_like "a logged command", "hello"
     end
 
     context "when debug mode is enabled via command option" do
       def subject_method
         sh.echo("hello", _debug: true)
       end
-
-      it "returns the command output" do
-        expect(subject_method).to eq("hello")
-      end
-
-      it "logs the command executed" do
-        subject_method
-
-        expect(log_output.join).to include("Executed: echo hello")
-      end
-
-      it "logs the duration" do
-        subject_method
-
-        expect(log_output.join).to match(/Duration: \d+\.\d+s/)
-      end
-
-      it "logs the pid" do
-        subject_method
-
-        expect(log_output.join).to match(/Pid: \d+/)
-      end
-
-      it "logs the exit code" do
-        subject_method
-
-        expect(log_output.join).to include("Exit code: 0")
-      end
-
-      it "logs the stdout" do
-        subject_method
-
-        expect(log_output.join).to include('Stdout: "hello"')
-      end
+      it_behaves_like "a logged command", "hello"
     end
 
     context "when debug mode is enabled globally" do
       before { RubyShell.debug = true }
 
-      def subject_method
-        sh.echo("world")
-      end
-
-      it "returns the command output" do
-        expect(subject_method).to eq("world")
+      context "when command is used as a method" do
+        def subject_method
+          sh.echo("world")
+        end
+        it_behaves_like "a logged command", "world"
       end
 
-      it "logs the command executed" do
-        subject_method
-
-        expect(log_output.join).to include("Executed: echo world")
-      end
-
-      it "logs the duration" do
-        subject_method
-
-        expect(log_output.join).to match(/Duration: \d+\.\d+s/)
-      end
-
-      it "logs the pid" do
-        subject_method
-
-        expect(log_output.join).to match(/Pid: \d+/)
-      end
-
-      it "logs the exit code" do
-        subject_method
-
-        expect(log_output.join).to include("Exit code: 0")
-      end
-
-      it "logs the stdout" do
-        subject_method
-
-        expect(log_output.join).to include('Stdout: "world"')
+      context "when command is executed in a block" do
+        def subject_method
+          sh { echo("world") }
+        end
+        it_behaves_like "a logged command", "world"
       end
     end
   end