diff --git a/CHANGELOG b/CHANGELOG
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,11 @@
+shell-monad (0.0.3) unstable; urgency=medium
+
+  * Added Output data type, which alows cmd to accept (Output (Script ()))
+    as a parameter.
+  * Better Quoted data type.
+
+ -- Joey Hess <id@joeyh.name>  Thu, 25 Dec 2014 12:07:04 -0400
+
 shell-monad (0.0.2) unstable; urgency=medium
 
   * Better constructing of pipes.
diff --git a/Control/Monad/Shell.hs b/Control/Monad/Shell.hs
--- a/Control/Monad/Shell.hs
+++ b/Control/Monad/Shell.hs
@@ -4,6 +4,7 @@
 {-# LANGUAGE FlexibleInstances #-}
 {-# LANGUAGE TypeFamilies #-}
 {-# LANGUAGE DeriveFunctor #-}
+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
 
 module Control.Monad.Shell (
 	Script,
@@ -11,13 +12,12 @@
 	linearScript,
 	Var,
 	val,
-	Q,
+	Quoted,
 	quote,
-	Expr,
-	indent,
 	run,
 	cmd,
-	add,
+	CmdArg,
+	Output(..),
 	comment,
 	newVar,
 	newVarContaining,
@@ -45,23 +45,19 @@
 	deriving (Eq, Ord, Show)
 
 -- | Expand a shell variable to its value.
-val :: Var -> Q
+val :: Var -> Quoted L.Text
 val (Var v) = Q ("\"$" <> v <> "\"")
 
--- | A piece of text that is safely quoted.
-newtype Q = Q { getQ :: L.Text }
-	deriving (Eq, Ord, Show)
-
-instance Monoid Q where
-	mempty = Q L.empty
-	mappend (Q a) (Q b) = Q (a <> b)
+-- | A value that is safely quoted.
+newtype Quoted a = Q { getQ :: a }
+	deriving (Eq, Ord, Show, Monoid)
 
 -- | Quotes the value to allow it to be safely exposed to the shell.
 --
 -- The method used is to replace ' with '"'"' and wrap the value inside
 -- single quotes. This works for POSIX shells, as well as other shells
 -- like csh.
-quote :: L.Text -> Q
+quote :: L.Text -> Quoted L.Text
 quote t
 	| L.all (isAlphaNum) t = Q t
 	| otherwise = Q $ q <> L.intercalate "'\"'\"'" (L.splitOn q t) <> q
@@ -167,9 +163,7 @@
 
 -- | Variadic argument version of 'run'.
 --
--- The command can be passed any number of arguments.
--- As well as passing Text and Q arguments, it also accepts Var arguments,
--- which passes the value of a shell variable to the command.
+-- The command can be passed any number of CmdArgs.
 --
 -- Convenient usage of 'cmd' requires the following:
 --
@@ -192,15 +186,22 @@
 class CmdArg a where
 	toTextArg :: a -> L.Text
 
+-- | Text arguments are automatically quoted.
 instance CmdArg L.Text where
 	toTextArg = getQ . quote
 
+-- | Var arguments cause the (quoted) value of a shell variable to be
+-- passed to the command.
 instance CmdArg Var where
 	toTextArg v = toTextArg (val v)
 
-instance CmdArg Q where
+-- | Quoted Text arguments are passed as-is.
+instance CmdArg (Quoted L.Text) where
 	toTextArg (Q v) = v
 
+instance CmdArg Output where
+	toTextArg (Output s) = "\"$(" <> linearScript s <> ")\""
+
 class ShellCmd t where
 	cmdAll :: L.Text -> [L.Text] -> t
 
@@ -210,6 +211,15 @@
 instance (f ~ ()) => ShellCmd (Script f) where
 	cmdAll c acc = add $ Cmd $ L.intercalate " " (c:reverse acc)
 
+-- | The output of a command, or even a more complicated Script
+-- can be passed as a parameter to 'cmd'
+--
+-- Examples:
+--
+-- > cmd "echo" "hello there," (Output (cmd "whoami"))
+-- > cmd "echo" "root's pwent" (Output (cmd "cat" "/etc/passwd" -|- cmd "grep" "root"))
+newtype Output = Output (Script ())
+
 -- | Adds an Expr to the script.
 add :: Expr -> Script ()
 add expr = Script $ \env -> ([expr], env, ())
@@ -221,8 +231,8 @@
 -- | Defines a new shell variable.
 --
 -- The name of the variable that appears in the shell script will be based
--- on provided name, but each call to newVar will generate a new, unique
--- variable name.
+-- on provided name (which can be mempty), but each call to newVar will
+-- generate a new, unique variable name.
 newVar
 	:: L.Text -- ^ base of variable name
 	-> Script Var
@@ -347,7 +357,7 @@
 	add $ Cmd $ word <> " :"
 	mapM_ (add . indent) =<< runM s
 
--- | Generates shell code to read a variable from stdin.
+-- | Generates shell code to fill a variable with a line read from stdin.
 readVar :: Var -> Script ()
 readVar (Var vname) = add $ Cmd $ "read " <> getQ (quote vname)
 
diff --git a/shell-monad.cabal b/shell-monad.cabal
--- a/shell-monad.cabal
+++ b/shell-monad.cabal
@@ -1,5 +1,5 @@
 Name: shell-monad
-Version: 0.0.2
+Version: 0.0.3
 Cabal-Version: >= 1.8
 License: BSD3
 Maintainer: Joey Hess <id@joeyh.name>