diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,11 @@
 # Revision history for irc-core
 
+## 2.3.0 -- 2017-06-02
+
+* Change type of `idDenote` to save a bit of memory
+* Add more commands to `Irc.Commands`
+* Fix comments
+
 ## 2.2.1 -- 2017-05-13
 
 * Prettier reply code text
diff --git a/irc-core.cabal b/irc-core.cabal
--- a/irc-core.cabal
+++ b/irc-core.cabal
@@ -1,5 +1,5 @@
 name:                irc-core
-version:             2.2.1
+version:             2.3.0
 synopsis:            IRC core library for glirc
 description:         IRC core library for glirc
                      .
diff --git a/src/Irc/Codes.hs b/src/Irc/Codes.hs
--- a/src/Irc/Codes.hs
+++ b/src/Irc/Codes.hs
@@ -38,7 +38,7 @@
 data ReplyType
   = ClientServerReply -- ^ 0-99 Messages between client and server
   | CommandReply      -- ^ 200-399 Responses to commands
-  | ErrorReply        -- ^ 200-399 Errors
+  | ErrorReply        -- ^ 400-599 Errors
   | UnknownReply      -- ^ Uncategorized
   deriving (Eq, Ord, Read, Show)
 
diff --git a/src/Irc/Commands.hs b/src/Irc/Commands.hs
--- a/src/Irc/Commands.hs
+++ b/src/Irc/Commands.hs
@@ -9,23 +9,35 @@
 This module provides smart constructors for IRC commands.
 -}
 module Irc.Commands
-  ( ircAway
+  ( ircAdmin
+  , ircAway
   , ircCapEnd
   , ircCapLs
   , ircCapReq
+  , ircCnotice
+  , ircCprivmsg
+  , ircInfo
   , ircInvite
   , ircIson
   , ircJoin
   , ircKick
+  , ircKill
+  , ircKnock
   , ircLinks
+  , ircList
+  , ircLusers
+  , ircMap
   , ircMode
+  , ircMotd
   , ircNick
   , ircNotice
+  , ircOper
   , ircPart
   , ircPass
   , ircPing
   , ircPong
   , ircPrivmsg
+  , ircRules
   , ircQuit
   , ircRemove
   , ircStats
@@ -36,6 +48,7 @@
   , ircWho
   , ircWhois
   , ircWhowas
+  , ircVersion
 
   -- * ZNC support
   , ircZnc
@@ -53,6 +66,9 @@
 import qualified Data.Text.Encoding as Text
 import qualified Data.ByteString.Base64 as Enc
 
+nonempty :: Text -> [Text]
+nonempty txt = filter (not . Text.null) [txt]
+
 -- | PRIVMSG command
 ircPrivmsg ::
   Text {- ^ target  -} ->
@@ -60,6 +76,35 @@
   RawIrcMsg
 ircPrivmsg who msg = rawIrcMsg "PRIVMSG" [who, msg]
 
+-- | CPRIVMSG command
+--
+-- > CPRIVMSG <nickname> <channel> :<message>
+ircCprivmsg ::
+  Text {- ^ nickname -} ->
+  Text {- ^ channel  -} ->
+  Text {- ^ message  -} ->
+  RawIrcMsg
+ircCprivmsg nick chan msg = rawIrcMsg "CPRIVMSG" [nick, chan, msg]
+
+-- | CNOTICE command
+--
+-- > CNOTICE <nickname> <channel> :<message>
+ircCnotice ::
+  Text {- ^ nickname -} ->
+  Text {- ^ channel  -} ->
+  Text {- ^ message  -} ->
+  RawIrcMsg
+ircCnotice nick chan msg = rawIrcMsg "CNOTICE" [nick, chan, msg]
+
+-- | KNOCK command
+--
+-- > KNOCK <channel> [<message>]
+ircKnock ::
+  Text {- ^ channel  -} ->
+  Text {- ^ message  -} ->
+  RawIrcMsg
+ircKnock chan msg = rawIrcMsg "KNOCK" (chan : nonempty msg)
+
 -- | NOTICE command
 ircNotice ::
   Text {- ^ target  -} ->
@@ -92,6 +137,12 @@
   RawIrcMsg
 ircWhowas = rawIrcMsg "WHOWAS"
 
+-- | WALLOPS command
+ircWallops ::
+  Text {- ^ message -} ->
+  RawIrcMsg
+ircWallops msg = rawIrcMsg "WALLOPS" [msg]
+
 -- | NICK command
 ircNick ::
   Text {- ^ nickname -} ->
@@ -103,9 +154,7 @@
   Identifier {- ^ channel -} ->
   Text       {- ^ message -} ->
   RawIrcMsg
-ircPart chan msg
-  | Text.null msg = rawIrcMsg "PART" [idText chan]
-  | otherwise     = rawIrcMsg "PART" [idText chan, msg]
+ircPart chan msg = rawIrcMsg "PART" (idText chan : nonempty msg)
 
 -- | JOIN command
 ircJoin ::
@@ -127,9 +176,7 @@
   Identifier {- ^ channel -} ->
   Text       {- ^ topic   -} ->
   RawIrcMsg
-ircTopic chan msg
-  | Text.null msg = rawIrcMsg "TOPIC" [idText chan]
-  | otherwise     = rawIrcMsg "TOPIC" [idText chan, msg]
+ircTopic chan msg = rawIrcMsg "TOPIC" (idText chan : nonempty msg)
 
 -- | KICK command
 ircKick ::
@@ -137,30 +184,37 @@
   Text       {- ^ nickname -} ->
   Text       {- ^ message  -} ->
   RawIrcMsg
-ircKick chan who msg
-  | Text.null msg = rawIrcMsg "KICK" [idText chan, who]
-  | otherwise     = rawIrcMsg "KICK" [idText chan, who, msg]
+ircKick chan who msg = rawIrcMsg "KICK" (idText chan : who : nonempty msg)
 
+-- | KILL command
+ircKill ::
+  Text {- ^ client  -} ->
+  Text {- ^ message -} ->
+  RawIrcMsg
+ircKill who msg = rawIrcMsg "KILL" (who : nonempty msg)
+
 -- | REMOVE command
 ircRemove ::
   Identifier {- ^ channel  -} ->
   Text       {- ^ nickname -} ->
   Text       {- ^ message  -} ->
   RawIrcMsg
-ircRemove chan who msg
-  | Text.null msg = rawIrcMsg "REMOVE" [idText chan, who]
-  | otherwise     = rawIrcMsg "REMOVE" [idText chan, who, msg]
+ircRemove chan who msg = rawIrcMsg "REMOVE" (idText chan : who : nonempty msg)
 
 -- | QUIT command
 ircQuit :: Text {- ^ quit message -} -> RawIrcMsg
-ircQuit msg
-  | Text.null msg = rawIrcMsg "QUIT" []
-  | otherwise     = rawIrcMsg "QUIT" [msg]
+ircQuit = rawIrcMsg "QUIT" . nonempty
 
 -- | PASS command
 ircPass :: Text {- ^ password -} -> RawIrcMsg
 ircPass pass = rawIrcMsg "PASS" [pass]
 
+-- | LIST command
+ircList ::
+  [Text] {- ^ parameters -} ->
+  RawIrcMsg
+ircList = rawIrcMsg "LIST"
+
 -- | PING command
 ircPing ::
   [Text] {- ^ parameters -} ->
@@ -181,9 +235,9 @@
 
 -- | TIME command
 ircTime ::
-  [Text] {- ^ parameters -} ->
+  Text {- ^ servername -} ->
   RawIrcMsg
-ircTime = rawIrcMsg "TIME"
+ircTime = rawIrcMsg "TIME" . nonempty
 
 -- | USERHOST command
 ircUserhost ::
@@ -191,12 +245,31 @@
   RawIrcMsg
 ircUserhost = rawIrcMsg "USERHOST"
 
+-- | USERIP command
+ircUserip ::
+  [Text] {- ^ parameters -} ->
+  RawIrcMsg
+ircUserip = rawIrcMsg "USERIP"
+
+-- | USERS command
+ircUsers ::
+  Text {- ^ server -} ->
+  RawIrcMsg
+ircUsers = rawIrcMsg "USERS" . nonempty
+
 -- | STATS command
 ircStats ::
   [Text] {- ^ parameters -} ->
   RawIrcMsg
 ircStats = rawIrcMsg "STATS"
 
+-- | OPER command
+ircOper ::
+  Text {- ^ username -} ->
+  Text {- ^ password -} ->
+  RawIrcMsg
+ircOper u p = rawIrcMsg "OPER" [u,p]
+
 -- | LINKS command
 ircLinks ::
   [Text] {- ^ parameters -} ->
@@ -207,9 +280,51 @@
 ircAway ::
   Text {- ^ message -} ->
   RawIrcMsg
-ircAway msg
-  | Text.null msg = rawIrcMsg "AWAY" []
-  | otherwise     = rawIrcMsg "AWAY" [msg]
+ircAway = rawIrcMsg "AWAY" . nonempty
+
+-- | MAP command
+ircMap :: RawIrcMsg
+ircMap = rawIrcMsg "MAP" []
+
+-- | INFO command
+ircInfo :: RawIrcMsg
+ircInfo = rawIrcMsg "INFO" []
+
+-- | RULES command
+ircRules ::
+  Text {- ^ servername -} ->
+  RawIrcMsg
+ircRules = rawIrcMsg "RULES" . nonempty
+
+-- | VERSION command
+ircVersion ::
+  Text {- ^ server -} ->
+  RawIrcMsg
+ircVersion = rawIrcMsg "VERSION" . nonempty
+
+-- | LUSERS command
+--
+-- > LUSERS [<mask> [<server>]]
+ircLusers ::
+  [Text] {- ^ params -} ->
+  RawIrcMsg
+ircLusers = rawIrcMsg "LUSERS"
+
+-- | MOTD command
+--
+-- > MOTD [<server>]
+ircMotd ::
+  Text {- ^ server -} ->
+  RawIrcMsg
+ircMotd = rawIrcMsg "MOTD" . nonempty
+
+-- | ADMIN command
+--
+-- > ADMIN [<target>]
+ircAdmin ::
+  Text {- ^ target -} ->
+  RawIrcMsg
+ircAdmin = rawIrcMsg "ADMIN" . nonempty
 
 -- | USER command
 ircUser ::
diff --git a/src/Irc/Identifier.hs b/src/Irc/Identifier.hs
--- a/src/Irc/Identifier.hs
+++ b/src/Irc/Identifier.hs
@@ -16,50 +16,69 @@
   , idDenote
   , mkId
   , idText
+  , idTextNorm
   , idPrefix
   ) where
 
+import           Control.Monad.ST
 import           Data.ByteString (ByteString)
 import qualified Data.ByteString as B
 import           Data.Char
+import           Data.Foldable
 import           Data.Function
 import           Data.Hashable
+import           Data.Monoid
 import           Data.Primitive.ByteArray
 import           Data.String
 import           Data.Text (Text)
+import qualified Data.Text as Text
 import qualified Data.Text.Encoding as Text
 import qualified Data.Vector.Primitive as PV
+import qualified Data.Primitive.ByteArray as BA
+import           Data.Primitive.ByteArray (ByteArray)
 import           Data.Word
 
 -- | Identifier representing channels and nicknames
 data Identifier = Identifier {-# UNPACK #-} !Text
-                             {-# UNPACK #-} !(PV.Vector Word8)
+                             {-# UNPACK #-} !ByteArray
 
+-- | This indexing function exists to specialize the type
+-- of 'BA.indexByteArray'.
+indexWord8 :: ByteArray -> Int -> Word8
+indexWord8 = BA.indexByteArray
+
 -- | Equality on normalized identifier
 instance Eq Identifier where
-  (==) = (==) `on` idDenote
+  Identifier _ x == Identifier _ y =
+    BA.sizeofByteArray x == BA.sizeofByteArray y &&
+    all (\i -> indexWord8 x i == indexWord8 y i)
+        [0 .. BA.sizeofByteArray x - 1]
 
+-- | Show as string literal
 instance Show Identifier where
   show = show . idText
 
+-- | Read as string literal
 instance Read Identifier where
   readsPrec p x = [ (mkId t, rest) | (t,rest) <- readsPrec p x]
 
 -- | Comparison on normalized identifier
 instance Ord Identifier where
-  compare = compare `on` idDenote
+  compare (Identifier _ x) (Identifier _ y) =
+    mconcat [ indexWord8 x i `compare` indexWord8 y i | i <- [0..n-1]]
+      <> (BA.sizeofByteArray x `compare` BA.sizeofByteArray y)
+    where
+      n = min (BA.sizeofByteArray x) (BA.sizeofByteArray y)
 
 -- | Hash on normalized identifier
 instance Hashable Identifier where
-  hashWithSalt s = hashPV8WithSalt s . idDenote
+  hashWithSalt salt (Identifier _ b@(ByteArray arr)) =
+    hashByteArrayWithSalt arr 0 (BA.sizeofByteArray b) salt
 
+-- | @'fromString' = 'mkId' . 'fromString'
 instance IsString Identifier where
   fromString = mkId . fromString
 
-hashPV8WithSalt :: Int -> PV.Vector Word8 -> Int
-hashPV8WithSalt salt (PV.Vector off len (ByteArray arr)) =
-  hashByteArrayWithSalt arr off len salt
-
 -- | Construct an 'Identifier' from a 'ByteString'
 mkId :: Text -> Identifier
 mkId x = Identifier x (ircFoldCase (Text.encodeUtf8 x))
@@ -68,19 +87,34 @@
 idText :: Identifier -> Text
 idText (Identifier x _) = x
 
--- | Returns the case-normalized 'ByteString' of an 'Identifier'
--- which is suitable for comparison or hashing.
-idDenote :: Identifier -> PV.Vector Word8
+-- | Returns a 'ByteArray' of an 'Identifier'
+-- which is suitable for comparison or hashing
+-- which has been normalized for case.
+idDenote :: Identifier -> ByteArray
 idDenote (Identifier _ x) = x
 
+-- | Returns the case-normalized 'Text' for an identifier.
+idTextNorm :: Identifier -> Text
+idTextNorm (Identifier _ x) =
+  Text.decodeUtf8
+    (B.pack [ indexWord8 x i | i <- [0 .. BA.sizeofByteArray x - 1]])
+
 -- | Returns 'True' when the first argument is a prefix of the second.
 idPrefix :: Identifier -> Identifier -> Bool
-idPrefix (Identifier _ x) (Identifier _ y) = x == PV.take (PV.length x) y
+idPrefix (Identifier _ x) (Identifier _ y) =
+  BA.sizeofByteArray x <= BA.sizeofByteArray y &&
+  all (\i -> indexWord8 x i == indexWord8 y i)
+      [0 .. BA.sizeofByteArray x - 1]
 
 -- | Capitalize a string according to RFC 2812
 -- Latin letters are capitalized and {|}~ are mapped to [\]^
-ircFoldCase :: ByteString -> PV.Vector Word8
-ircFoldCase = PV.fromList . map (\i -> casemap PV.! fromIntegral i) . B.unpack
+ircFoldCase :: ByteString -> ByteArray
+ircFoldCase bs = runST $
+  do let n = B.length bs
+     a <- BA.newByteArray n
+     for_ [0..n-1] $ \i ->
+       BA.writeByteArray a i (casemap PV.! fromIntegral (B.index bs i))
+     BA.unsafeFreezeByteArray a
 
 casemap :: PV.Vector Word8
 casemap