Fix #1196

lib/pry/commands/bang.rb

@@ -1,6 +1,6 @@
 class Pry
   class Command::Bang < Pry::ClassCommand
-    match '!'
+    match /^\s*!\s*$/
     group 'Editing'
     description 'Clear the input buffer.'
     command_options :use_prefix => false

spec/commands/bang_spec.rb

@@ -15,4 +15,10 @@ describe "!" do
     @t.last_output.should =~ /Input buffer cleared!/
     @t.eval_string.should == ''
   end
+
+  it 'should not clear the input buffer for negation' do
+    @t.push '! false'
+    @t.last_output.should =~ /true/
+    @t.eval_string.should == ''
+  end
 end