diff --git a/cmd/ledis-cli/const.go b/cmd/ledis-cli/const.go
index a3e0674..9fc72dd 100644
--- a/cmd/ledis-cli/const.go
+++ b/cmd/ledis-cli/const.go
@@ -1,4 +1,4 @@
-//This file was generated by .tools/generate_commands.py on Fri Feb 06 2015 09:15:18 +0800
+//This file was generated by .tools/generate_commands.py on Mon Mar 02 2015 14:43:25 +0800 
 package main
 
 var helpCommands = [][]string{
@@ -20,8 +20,6 @@ var helpCommands = [][]string{
 	{"BRPOP", "key [key ...] timeout", "List"},
 	{"BSETBIT", "key offset value", "Bitmap"},
 	{"BTTL", "key", "Bitmap"},
-	{"BXREVSCAN", "key [MATCH match] [COUNT count]", "Bitmap"},
-	{"BXSCAN", "key [MATCH match] [COUNT count]", "Bitmap"},
 	{"COMMIT", "-", "Transaction"},
 	{"CONFIG REWRITE", "-", "Server"},
 	{"DECR", "key", "KV"},
@@ -59,8 +57,6 @@ var helpCommands = [][]string{
 	{"HSET", "key field value", "Hash"},
 	{"HTTL", "key", "Hash"},
 	{"HVALS", "key", "Hash"},
-	{"HXREVSCAN", "key [MATCH match] [COUNT count]", "Hash"},
-	{"HXSCAN", "key [MATCH match] [COUNT count]", "Hash"},
 	{"INCR", "key", "KV"},
 	{"INCRBY", "key increment", "KV"},
 	{"INFO", "[section]", "Server"},
@@ -76,8 +72,6 @@ var helpCommands = [][]string{
 	{"LPUSH", "key value [value ...]", "List"},
 	{"LRANGE", "key start stop", "List"},
 	{"LTTL", "key", "List"},
-	{"LXREVSCAN", "key [MATCH match] [COUNT count]", "List"},
-	{"LXSCAN", "key [MATCH match] [COUNT count]", "List"},
 	{"MGET", "key [key ...]", "KV"},
 	{"MSET", "key value [key value ...]", "KV"},
 	{"PERSIST", "key", "KV"},
@@ -116,23 +110,13 @@ var helpCommands = [][]string{
 	{"STTL", "key", "Set"},
 	{"SUNION", "key [key ...]", "Set"},
 	{"SUNIONSTORE", "destination key [key ...]", "Set"},
-	{"SXREVSCAN", "key [MATCH match] [COUNT count]", "Set"},
-	{"SXSCAN", "key [MATCH match] [COUNT count]", "Set"},
 	{"SYNC", "logid", "Replication"},
 	{"TIME", "-", "Server"},
 	{"TTL", "key", "KV"},
-	{"XBREVSCAN", "key [MATCH match] [COUNT count]", "Bitmap"},
-	{"XBSCAN", "key [MATCH match] [COUNT count]", "Bitmap"},
-	{"XHREVSCAN", "key [MATCH match] [COUNT count]", "Hash"},
-	{"XHSCAN", "key [MATCH match] [COUNT count]", "Hash"},
-	{"XLREVSCAN", "key [MATCH match] [COUNT count]", "List"},
-	{"XLSCAN", "key [MATCH match] [COUNT count]", "List"},
-	{"XREVSCAN", "key [MATCH match] [COUNT count]", "KV"},
-	{"XSCAN", "key [MATCH match] [COUNT count]", "KV"},
-	{"XSREVSCAN", "key [MATCH match] [COUNT count]", "Set"},
-	{"XSSCAN", "key [MATCH match] [COUNT count]", "Set"},
-	{"XZREVSCAN", "key [MATCH match] [COUNT count]", "ZSet"},
-	{"XZSCAN", "key [MATCH match] [COUNT count]", "ZSet"},
+	{"XHSCAN", "key cursor [MATCH match] [COUNT count]", "Hash"},
+	{"XSCAN", "type cursor [MATCH match] [COUNT count]", "Server"},
+	{"XSSCAN", "key cursor [MATCH match] [COUNT count]", "Set"},
+	{"XZSCAN", "key cursor [MATCH match] [COUNT count]", "ZSet"},
 	{"ZADD", "key score member [score member ...]", "ZSet"},
 	{"ZCARD", "key", "ZSet"},
 	{"ZCLEAR", "key", "ZSet"},
@@ -159,6 +143,4 @@ var helpCommands = [][]string{
 	{"ZSCORE", "key member", "ZSet"},
 	{"ZTTL", "key", "ZSet"},
 	{"ZUNIONSTORE", "destkey numkeys key [key ...] [WEIGHTS weight [weight ...]] [AGGREGATE SUM|MIN|MAX]", "ZSet"},
-	{"ZXREVSCAN", "key [MATCH match] [COUNT count]", "ZSet"},
-	{"ZXSCAN", "key [MATCH match] [COUNT count]", "ZSet"},
 }
diff --git a/doc/commands.json b/doc/commands.json
index 4b549db..281fd07 100644
--- a/doc/commands.json
+++ b/doc/commands.json
@@ -560,79 +560,7 @@
         "group": "Transaction",
         "readonly": false
     },
-
-    "XSCAN": {
-        "arguments": "key [MATCH match] [COUNT count]",
-        "group": "KV",
-        "readonly": true
-    },
-
-    "HXSCAN": {
-        "arguments": "key [MATCH match] [COUNT count]",
-        "group": "Hash",
-        "readonly": true
-    },
-
-    "LXSCAN": {
-        "arguments": "key [MATCH match] [COUNT count]",
-        "group": "List",
-        "readonly": true
-    },
-
-    "SXSCAN": {
-        "arguments": "key [MATCH match] [COUNT count]",
-        "group": "Set",
-        "readonly": true
-    },
-
-    "ZXSCAN": {
-        "arguments": "key [MATCH match] [COUNT count]",
-        "group": "ZSet",
-        "readonly": true
-    },
-
-    "BXSCAN": {
-        "arguments": "key [MATCH match] [COUNT count]",
-        "group": "Bitmap",
-        "readonly": true
-    },
-    
-    "XREVSCAN": {
-        "arguments": "key [MATCH match] [COUNT count]",
-        "group": "KV",
-        "readonly": true
-    },
-
-    "HXREVSCAN": {
-        "arguments": "key [MATCH match] [COUNT count]",
-        "group": "Hash",
-        "readonly": true
-    },
-
-    "LXREVSCAN": {
-        "arguments": "key [MATCH match] [COUNT count]",
-        "group": "List",
-        "readonly": true
-    },
-
-    "SXREVSCAN": {
-        "arguments": "key [MATCH match] [COUNT count]",
-        "group": "Set",
-        "readonly": true
-    },
-
-    "ZXREVSCAN": {
-        "arguments": "key [MATCH match] [COUNT count]",
-        "group": "ZSet",
-        "readonly": true
-    },
-
-    "BXREVSCAN": {
-        "arguments": "key [MATCH match] [COUNT count]",
-        "group": "Bitmap",
-        "readonly": true
-    },
-
+ 
     "FLUSHALL": {
         "arguments": "-",
         "group": "Server",
@@ -724,66 +652,30 @@
         "readonly": true
     },
 
-    "XBSCAN": {
-        "arguments": "key [MATCH match] [COUNT count]",
-        "group": "Bitmap",
-        "readonly": true
-    },
-
-    "XLSCAN": {
-        "arguments": "key [MATCH match] [COUNT count]",
-        "group": "List",
+    "XSCAN": {
+        "arguments": "type cursor [MATCH match] [COUNT count]",
+        "group": "Server",
         "readonly": true
     },
 
     "XHSCAN": {
-        "arguments": "key [MATCH match] [COUNT count]",
+        "arguments": "key cursor [MATCH match] [COUNT count]",
         "group": "Hash",
         "readonly": true
     },
 
     "XSSCAN": {
-        "arguments": "key [MATCH match] [COUNT count]",
+        "arguments": "key cursor [MATCH match] [COUNT count]",
         "group": "Set",
         "readonly": true
     },
 
     "XZSCAN": {
-        "arguments": "key [MATCH match] [COUNT count]",
+        "arguments": "key cursor [MATCH match] [COUNT count]",
         "group": "ZSet",
         "readonly": true
     },
 
-    "XHREVSCAN": {
-        "arguments": "key [MATCH match] [COUNT count]",
-        "group": "Hash",
-        "readonly": true
-    },
-
-    "XLREVSCAN": {
-        "arguments": "key [MATCH match] [COUNT count]",
-        "group": "List",
-        "readonly": true
-    },
-
-    "XSREVSCAN": {
-        "arguments": "key [MATCH match] [COUNT count]",
-        "group": "Set",
-        "readonly": true
-    },
-
-    "XZREVSCAN": {
-        "arguments": "key [MATCH match] [COUNT count]",
-        "group": "ZSet",
-        "readonly": true
-    },
-
-    "XBREVSCAN": {
-        "arguments": "key [MATCH match] [COUNT count]",
-        "group": "Bitmap",
-        "readonly": true
-    },
-
     "RESTORE": {
         "arguments" : "key ttl value",
         "group" : "Server",
diff --git a/doc/commands.md b/doc/commands.md
index 1cde082..2e4bce6 100644
--- a/doc/commands.md
+++ b/doc/commands.md
@@ -27,8 +27,6 @@ Table of Contents
 	- [EXPIREAT key timestamp](#expireat-key-timestamp)
 	- [TTL key](#ttl-key)
 	- [PERSIST key](#persist-key)
-	- [XSCAN key [MATCH match] [COUNT count]](#xscan-key-match-match-count-count)
-	- [XREVSCAN key [MATCH match] [COUNT count]](#xrevscan-key-match-match-count-count)
 	- [DUMP key](#dump-key)
 - [Hash](#hash)
 	- [HDEL key field [field ...]](#hdel-key-field-field-)
@@ -48,10 +46,6 @@ Table of Contents
 	- [HEXPIREAT key timestamp](#hexpireat-key-timestamp)
 	- [HTTL key](#httl-key)
 	- [HPERSIST key](#hpersist-key)
-	- [HXSCAN key [MATCH match] [COUNT count]](#hxscan-key-match-match-count-count)
-	- [HXREVSCAN key [MATCH match] [COUNT count]](#hxrevscan-key-match-match-count-count)
-	- [XHSCAN key [MATCH match] [COUNT count]](#xhscan-key-match-match-count-count)
-	- [XHREVSCAN key [MATCH match] [COUNT count]](#xhrevscan-key-match-match-count-count)
 	- [HDUMP key](#hdump-key)
 - [List](#list)
 	- [BLPOP key [key ...] timeout](#blpop-key-key--timeout)
@@ -69,10 +63,6 @@ Table of Contents
 	- [LEXPIREAT key timestamp](#lexpireat-key-timestamp)
 	- [LTTL key](#lttl-key)
 	- [LPERSIST key](#lpersist-key)
-	- [LXSCAN key [MATCH match] [COUNT count]](#lxscan-key-match-match-count-count)
-	- [LXREVSCAN key [MATCH match] [COUNT count]](#lxrevscan-key-match-match-count-count)
-	- [XLSCAN key [MATCH match] [COUNT count]](#xlscan-key-match-match-count-count)
-	- [XLREVSCAN key [MATCH match] [COUNT count]](#xlrevscan-key-match-match-count-count)
 	- [LDUMP key](#ldump-key)
 - [Set](#set)
 	- [SADD key member [member ...]](#sadd-key-member-member-)
@@ -92,10 +82,6 @@ Table of Contents
 	- [SEXPIREAT key timestamp](#sexpireat-key-timestamp)
 	- [STTL key](#sttl-key)
 	- [SPERSIST key](#spersist-key)
-	- [SXSCAN key [MATCH match] [COUNT count]](#sxscan-key-match-match-count-count)
-	- [SXREVSCAN key [MATCH match] [COUNT count]](#sxrevscan-key-match-match-count-count)
-	- [XSSCAN key [MATCH match] [COUNT count]](#xsscan-key-match-match-count-count)
-	- [XSREVSCAN key [MATCH match] [COUNT count]](#xsrevscan-key-match-match-count-count)
 	- [SDUMP key](#sdump-key)
 - [ZSet](#zset)
 	- [ZADD key score member [score member ...]](#zadd-key-score-member-score-member-)
@@ -122,10 +108,6 @@ Table of Contents
 ](#zunionstore-destination-numkeys-key-key--weights-weight-weight--aggregate-summinmax)
     - [ZINTERSTORE destination numkeys key [key ...] [WEIGHTS weight [weight ...]] [AGGREGATE SUM|MIN|MAX]
 ](#zinterstore-destination-numkeys-key-key--weights-weight-weight--aggregate-summinmax)
-	- [ZXSCAN key [MATCH match] [COUNT count]](#zxscan-key-match-match-count-count)
-	- [ZXREVSCAN key [MATCH match] [COUNT count]](#zxrevscan-key-match-match-count-count)
-	- [XZSCAN key [MATCH match] [COUNT count]](#xzscan-key-match-match-count-count)
-	- [XZREVSCAN key [MATCH match] [COUNT count]](#xzrevscan-key-match-match-count-count)
 	- [ZRANGEBYLEX key min max [LIMIT offset count]](#zrangebylex-key-min-max-limit-offset-count)
 	- [ZREMRANGEBYLEX key min max](#zremrangebylex-key-min-max)
 	- [ZLEXCOUNT key min max](#zlexcount-key-min-max)
@@ -141,10 +123,11 @@ Table of Contents
 	- [BEXPIREAT key timestamp](#bexpireat-key-timestamp)
 	- [BTTL key](#bttl-key)
 	- [BPERSIST key](#bpersist-key)
-	- [BXSCAN key [MATCH match] [COUNT count]](#bxscan-key-match-match-count-count)
-	- [BXREVSCAN key [MATCH match] [COUNT count]](#bxrevscan-key-match-match-count-count)
-	- [XBSCAN key [MATCH match] [COUNT count]](#xbscan-key-match-match-count-count)
-	- [XBREVSCAN key [MATCH match] [COUNT count]](#xbrevscan-key-match-match-count-count)
+- [Scan](#scan)
+	- [XSCAN type cursor [MATCH match] [COUNT count]](#xscan-type-cursor-match-match-count-count)
+	- [XHSCAN key cursor [MATCH match] [COUNT count]](#xhscan-key-cursor-match-match-count-count)
+	- [XSSCAN key cursor [MATCH match] [COUNT count]](#xsscan-key-cursor-match-match-count-count)
+	- [XZSCAN key cursor [MATCH match] [COUNT count]](#xzscan-key-cursor-match-match-count-count)
 - [Replication](#replication)
 	- [SLAVEOF host port [RESTART] [READONLY]](#slaveof-host-port-restart-readonly)
 	- [FULLSYNC [NEW]](#fullsync-new)
@@ -524,82 +507,6 @@ ledis> TTL mykey
 (integer) -1
 ```
 
-### XSCAN key [MATCH match] [COUNT count] 
-
-Iterate KV keys incrementally.
-
-Key is the start for the current iteration.
-Match is the regexp for checking matched key.
-Count is the maximum retrieved elememts number, default is 10.
-
-**Return value**
-
-an array of two values, first value is the key for next iteration, second value is an array of elements.
-
-**Examples**
-
-```
-ledis>set a 1
-OK
-ledis>set b 2
-OK
-ledis>set c 3
-OK
-127.0.0.1:6380>xscan "" 
-1) ""
-2) ["a" "b" "c"]
-ledis>xscan "" count 1
-1) "a"
-2) ["a"]
-ledis>xscan "a" count 1
-1) "b"
-2) ["b"]
-ledis>xscan "b" count 1
-1) "c"
-2) ["c"]
-ledis>xscan "c" count 1
-1) ""
-2) []
-```
-
-### XREVSCAN key [MATCH match] [COUNT count] 
-
-Reverse iterate KV keys incrementally.
-
-Key is the start for the current iteration.
-Match is the regexp for checking matched key.
-Count is the maximum retrieved elememts number, default is 10.
-
-**Return value**
-
-an array of two values, first value is the key for next iteration, second value is an array of elements.
-
-**Examples**
-
-```
-ledis>set a 1
-OK
-ledis>set b 2
-OK
-ledis>set c 3
-OK
-127.0.0.1:6380>xrevscan "" 
-1) ""
-2) ["c" "b" "a"]
-ledis>xrevscan "" count 1
-1) "c"
-2) ["c"]
-ledis>xrevscan "c" count 1
-1) "b"
-2) ["b"]
-ledis>xrevscan "b" count 1
-1) "a"
-2) ["a"]
-ledis>xrevscan "a" count 1
-1) ""
-2) []
-```
-
 ### DUMP key
 
 Serialize the value stored at key with KV type in a Redis-specific format like RDB and return it to the user. The returned value can be synthesized back into a key using the RESTORE command.
@@ -980,31 +887,6 @@ ledis> HPERSIST not_exists_key
 (integer) 0
 ```
 
-### HXSCAN key [MATCH match] [COUNT count] 
-
-Iterate Hash keys incrementally.
-
-See [XSCAN](#xscan-key-match-match-count-count) for more information.
-
-### HXREVSCAN key [MATCH match] [COUNT count] 
-
-Reverse iterate Hash keys incrementally.
-
-See [XREVSCAN](#xrevscan-key-match-match-count-count) for more information.
-
-### XHSCAN key [MATCH match] [COUNT count] 
-
-Iterate Hash keys incrementally.
-
-See [XSCAN](#xscan-key-match-match-count-count) for more information.
-
-### XHREVSCAN key [MATCH match] [COUNT count] 
-
-Reverse iterate Hash keys incrementally.
-
-See [XREVSCAN](#xrevscan-key-match-match-count-count) for more information.
-
-
 ### HDUMP key
 
 See [DUMP](#dump-key) for more information.
@@ -1331,31 +1213,6 @@ ledis> LPERSIST b
 (integer) 0
 ```
 
-### LXSCAN key [MATCH match] [COUNT count] 
-
-Iterate list keys incrementally.
-
-See [XSCAN](#xscan-key-match-match-count-count) for more information.
-
-### LXREVSCAN key [MATCH match] [COUNT count] 
-
-Reverse iterate list keys incrementally.
-
-See [XREVSCAN](#xrevscan-key-match-match-count-count) for more information.
-
-### XLSCAN key [MATCH match] [COUNT count] 
-
-Iterate list keys incrementally.
-
-See [XSCAN](#xscan-key-match-match-count-count) for more information.
-
-### XLREVSCAN key [MATCH match] [COUNT count] 
-
-Reverse iterate list keys incrementally.
-
-See [XREVSCAN](#xrevscan-key-match-match-count-count) for more information.
-
-
 ### LDUMP key
 
 See [DUMP](#dump-key) for more information.
@@ -1782,33 +1639,6 @@ ledis> STTL key
 (integer) -1
 ```
 
-### SXSCAN key [MATCH match] [COUNT count] 
-
-Iterate Set keys incrementally.
-
-See [XSCAN](#xscan-key-match-match-count-count) for more information.
-
-
-### SXREVSCAN key [MATCH match] [COUNT count] 
-
-Reverse iterate Set keys incrementally.
-
-See [XREVSCAN](#xrevscan-key-match-match-count-count) for more information.
-
-### XSSCAN key [MATCH match] [COUNT count] 
-
-Iterate Set keys incrementally.
-
-See [XSCAN](#xscan-key-match-match-count-count) for more information.
-
-
-### XSREVSCAN key [MATCH match] [COUNT count] 
-
-Reverse iterate Set keys incrementally.
-
-See [XREVSCAN](#xrevscan-key-match-match-count-count) for more information.
-
-
 ### SDUMP key
 
 See [DUMP](#dump-key) for more information.
@@ -2432,30 +2262,6 @@ ledis> ZRANGE out 0 -1 WITHSCORES
 4) "10"
 ```
 
-### ZXSCAN key [MATCH match] [COUNT count] 
-
-Iterate ZSet keys incrementally.
-
-See [XSCAN](#xscan-key-match-match-count-count) for more information.
-
-### ZXREVSCAN key [MATCH match] [COUNT count] 
-
-Reverse iterate ZSet keys incrementally.
-
-See [XREVSCAN](#xrevscan-key-match-match-count-count) for more information.
-
-### XZSCAN key [MATCH match] [COUNT count] 
-
-Iterate ZSet keys incrementally.
-
-See [XSCAN](#xscan-key-match-match-count-count) for more information.
-
-### XZREVSCAN key [MATCH match] [COUNT count] 
-
-Reverse iterate ZSet keys incrementally.
-
-See [XREVSCAN](#xrevscan-key-match-match-count-count) for more information.
-
 ### ZRANGEBYLEX key min max [LIMIT offset count]
 
 When all the elements in a sorted set are inserted with the same score, in order to force lexicographical ordering, this command returns all the elements in the sorted set at key with a value between min and max.
@@ -2684,29 +2490,60 @@ ledis> BCOUNT flag 5 6
 (refer to [PERSIST](#persist-key) api for other types)
 
 
-### BXSCAN key [MATCH match] [COUNT count] 
+## Scan
 
-Iterate Bitmap keys incrementally.
+### XSCAN type cursor [MATCH match] [COUNT count]
 
-See [XSCAN](#xscan-key-match-match-count-count) for more information.
+Iterate data type keys incrementally.
 
-### BXREVSCAN key [MATCH match] [COUNT count] 
+Type is "KV", "LIST", "HASH", "SET" or "ZSET".
+Cursor is the start for the current iteration.
+Match is the regexp for checking matched key.
+Count is the maximum retrieved elememts number, default is 10.
 
-Reverse iterate Bitmap keys incrementally.
+**Return value**
 
-See [XREVSCAN](#xrevscan-key-match-match-count-count) for more information.
+an array of two values, first value is the cursor for next iteration, second value is an array of elements.
 
-### XBSCAN key [MATCH match] [COUNT count] 
+**Examples**
 
-Iterate Bitmap keys incrementally.
+```
+ledis>set a 1
+OK
+ledis>set b 2
+OK
+ledis>set c 3
+OK
+127.0.0.1:6380>xscan "KV" "" 
+1) ""
+2) ["a" "b" "c"]
+ledis>xscan "KV" "" count 1
+1) "a"
+2) ["a"]
+ledis>xscan "KV" "a" count 1
+1) "b"
+2) ["b"]
+ledis>xscan "KV" "b" count 1
+1) "c"
+2) ["c"]
+ledis>xscan "KV" "c" count 1
+1) ""
+2) []
+```
 
-See [XSCAN](#xscan-key-match-match-count-count) for more information.
+### XHSCAN key cursor [MATCH match] [COUNT count]
 
-### XBREVSCAN key [MATCH match] [COUNT count] 
+Same like [XSCAN type cursor [MATCH match] [COUNT count]](#xscan-type-cursor-match-match-count-count), but return array of elements 
+contains two elements, a field and a value. 
 
-Reverse iterate Bitmap keys incrementally.
+### XSSCAN key cursor [MATCH match] [COUNT count]
 
-See [XREVSCAN](#xrevscan-key-match-match-count-count) for more information.
+Same like [XSCAN type cursor [MATCH match] [COUNT count]](#xscan-type-cursor-match-match-count-count)
+
+### XZSCAN key cursor [MATCH match] [COUNT count]
+
+Same like [XSCAN type cursor [MATCH match] [COUNT count]](#xscan-type-cursor-match-match-count-count), but return array of elements 
+contains two elements, a member and its associated score. 
 
 
 ## Replication