Land #10423, history deduplication on add

Also removes history -u deduplication on print.

lib/msf/ui/console/command_dispatcher/core.rb

@@ -87,8 +87,7 @@ class Core
   @@history_opts = Rex::Parser::Arguments.new(
     "-h" => [ false, "Help banner."                                   ],
     "-a" => [ false, "Show all commands in history."                  ],
-    "-n" => [ true,  "Show the last n commands."                      ],
-    "-u" => [ false, "Show only unique commands."                     ])
+    "-n" => [ true,  "Show the last n commands."                      ])
 
   @@irb_opts = Rex::Parser::Arguments.new(
     "-h" => [ false, "Help banner."                                   ],
@@ -475,7 +474,6 @@ class Core
 
   def cmd_history(*args)
     length = Readline::HISTORY.length
-    uniq   = false
 
     if length < @history_limit
       limit = length
@@ -494,8 +492,6 @@ class Core
         else
           limit = val.to_i
         end
-      when "-u"
-        uniq = true
       when "-h"
         cmd_history_help
         return false
@@ -506,9 +502,6 @@ class Core
     pad_len = length.to_s.length
 
     (start..length-1).each do |pos|
-      if uniq && Readline::HISTORY[pos] == Readline::HISTORY[pos-1]
-        next unless pos == 0
-      end
       cmd_num = (pos + 1).to_s
       print_line "#{cmd_num.ljust(pad_len)}  #{Readline::HISTORY[pos]}"
     end
@@ -519,6 +512,7 @@ class Core
     print_line
     print_line "Shows the command history."
     print_line "If -n is not set, only the last #{@history_limit} commands will be shown."
+    print_line
     print @@history_opts.usage
   end
 

lib/rex/ui/text/input/readline.rb

@@ -168,7 +168,10 @@ begin
         end
 
         if add_history && line
-          RbReadline.add_history(line)
+          # Don't add duplicate lines to history
+          if ::Readline::HISTORY.empty? || line != ::Readline::HISTORY[-1]
+            RbReadline.add_history(line)
+          end
         end
 
         line.try(:dup)