diff --git a/Shelly.hs b/Shelly.hs
--- a/Shelly.hs
+++ b/Shelly.hs
@@ -21,7 +21,7 @@
 module Shelly
        (
          -- * Entering ShIO.
-         ShIO, shelly, sub, silently, verbosely, print_commands
+         ShIO, shelly, sub, silently, verbosely, jobs, print_commands
 
          -- * Running external commands.
          , run, run_, cmd, (-|-), lastStderr, setStdin
@@ -47,6 +47,9 @@
          , mv, rm_f, rm_rf, cp, cp_r, mkdir, mkdir_p
          , readfile, writefile, appendfile, withTmpDir
 
+         -- * Running external commands asynchronously.
+         , background, getBgResult, BgResult
+
          -- * exiting the program
          , exit, errorExit, terror
 
@@ -97,6 +100,7 @@
 import Control.Exception hiding (handle)
 import Control.Monad.Reader
 import Control.Concurrent
+import qualified Control.Concurrent.MSem as Sem
 import Data.Time.Clock( getCurrentTime, diffUTCTime  )
 
 import qualified Data.Text.Lazy.IO as TIO
@@ -500,6 +504,53 @@
 -- | Create a sub-ShIO in which external command outputs are echoed. See "sub".
 verbosely :: ShIO a -> ShIO a
 verbosely a = sub $ modify (\x -> x { sVerbose = True }) >> a
+
+-- | Create a sub-ShIO which has a 'limit' on the max number of background tasks.
+-- an invocation of jobs is independent of any others, and not tied to the ShIO monad in any way.
+-- This blocks the execution of the program until all 'background' jobs are finished.
+jobs :: Int -> (BgJobManager -> ShIO a) -> ShIO a
+jobs limit action = do
+    unless (limit > 0) $ terror "expected limit to be > 0"
+    availableJobsSem <- liftIO $ Sem.new limit
+    res <- action $ BgJobManager availableJobsSem
+    liftIO $ waitForJobs availableJobsSem
+    return res
+  where
+    waitForJobs sem = do
+      avail <- Sem.peekAvail sem
+      if avail == limit then return () else waitForJobs sem
+
+newtype BgJobManager = BgJobManager (Sem.MSem Int)
+
+-- | Type returned by tasks run asynchronously in the background.
+newtype BgResult a = BgResult (MVar a)
+
+-- | Returns the promised result from a backgrounded task.  Blocks until
+-- the task completes.
+getBgResult :: BgResult a -> ShIO a
+getBgResult (BgResult mvar) = liftIO $ takeMVar mvar
+
+-- | Run the `ShIO` task asynchronously in the background, returns
+-- the `BgResult a`, a promise immediately. Run "getBgResult" to wait for the result.
+-- The background task will inherit the current ShIO context
+-- The 'BjJobManager' ensures the max jobs limit must be sufficient for the parent and all children.
+background :: BgJobManager -> ShIO a -> ShIO (BgResult a)
+background (BgJobManager manager) proc = do
+  state <- get
+  liftIO $ do
+    -- take up a spot
+    -- It is important to do this before forkIO:
+    -- It ensures that that jobs will block and the program won't exit before our jobs are done
+    -- On the other hand, a user might not expect 'jobs' to block
+    Sem.wait manager
+    mvar <- newEmptyMVar -- future result
+
+    _<- forkIO $ do
+      result <- shelly $ (put state >> proc)
+      Sem.signal manager -- open a spot back up
+      liftIO $ putMVar mvar result
+    return $ BgResult mvar
+
 
 -- | Create a sub-ShIO in which external command outputs are echoed. See "sub".
 print_commands :: ShIO a -> ShIO a
diff --git a/shelly.cabal b/shelly.cabal
--- a/shelly.cabal
+++ b/shelly.cabal
@@ -1,6 +1,6 @@
 Name:       shelly
 
-Version:     0.6
+Version:     0.7
 Synopsis:    shell-like (systems) programming in Haskell
 
 Description: Shelly is a package provides a single module for convenient
@@ -32,6 +32,7 @@
   Exposed-modules:     Shelly
 
   Build-depends: base >= 4 && < 5, time, directory, text, mtl, process
+               , SafeSemaphore
                , unix-compat < 0.4
                , system-filepath < 0.5
                , system-fileio < 0.4
@@ -45,6 +46,7 @@
     ghc-options: -Wall
 
     Build-depends: base >= 4 && < 5, time, directory, text, mtl, process
+                 , SafeSemaphore
                  , unix-compat < 0.4
                  , system-filepath < 0.5
                  , system-fileio < 0.4
diff --git a/test/main.hs b/test/main.hs
--- a/test/main.hs
+++ b/test/main.hs
@@ -9,6 +9,14 @@
 main :: IO ()
 main =
   shelly $ do
+    jobs 2 $ \job -> do
+      background job $ cmd "sleep" "2"
+      echo "yawn"
+      background job $ cmd "sleep" "2"
+      echo "tired"
+      background job $ cmd "sleep" "2"
+      echo "zzzz"
+ 
     setStdin "in"
     echo "echo"
     setStdin "catted"