diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,3 +1,7 @@
+# 1.6.8.6
+
+* Fix Build issue [#156](https://github.com/yesodweb/Shelly.hs/issues/156)
+
 # 1.6.8.5
 
 * Fix Windows build [#155](https://github.com/yesodweb/Shelly.hs/pull/155)
diff --git a/shelly.cabal b/shelly.cabal
--- a/shelly.cabal
+++ b/shelly.cabal
@@ -1,154 +1,194 @@
-name: shelly
-version: 1.6.8.5
-cabal-version: >=1.8
-build-type: Simple
-license: BSD3
-license-file: LICENSE
-maintainer: Greg Weber <greg@gregweber.info>
-homepage: https://github.com/yesodweb/Shelly.hs
-synopsis: shell-like (systems) programming in Haskell
-description:
-    Shelly provides convenient systems programming in Haskell,
-    similar in spirit to POSIX shells. Shelly:
-    .
-    * is aimed at convenience and getting things done rather than
-    being a demonstration of elegance.
-    .
-    * has detailed and useful error messages
-    .
-    * maintains its own environment, making it thread-safe.
-    .
-    * is modern, using Text and system-filepath/system-fileio
-    .
-    Shelly is originally forked from the Shellish package.
-    .
-    See the shelly-extra package for additional functionality.
-    .
-    An overview is available in the README: <https://github.com/yesodweb/Shelly.hs/blob/master/README.md>
-category: Development
-author: Greg Weber, Petr Rockai
-extra-source-files:
-    test/src/*.hs
-    test/examples/*.sh
-    test/examples/*.hs
-    test/data/zshrc
-    test/data/nonascii.txt
-    test/testall
-    README.md
-    ChangeLog.md
+Name:       shelly
 
-source-repository head
-    type: git
-    location: https://github.com/yesodweb/Shelly.hs
+Version:     1.6.8.6
+Synopsis:    shell-like (systems) programming in Haskell
 
-flag lifted
-    description:
-        run the tests against Shelly.Lifted
-    default: False
+Description: Shelly provides convenient systems programming in Haskell,
+             similar in spirit to POSIX shells. Shelly:
+             .
+               * is aimed at convenience and getting things done rather than
+                 being a demonstration of elegance.
+             .
+               * has detailed and useful error messages
+             .
+               * maintains its own environment, making it thread-safe.
+             .
+               * is modern, using Text and system-filepath/system-fileio
+             .
+             Shelly is originally forked from the Shellish package.
+             .
+             See the shelly-extra package for additional functionality.
+             .
+             An overview is available in the README: <https://github.com/yesodweb/Shelly.hs/blob/master/README.md>
 
-flag build-examples
-    description:
-        build some example programs
-    default: False
-    manual: True
 
-library
-    
-    if impl(ghc >=7.6.1)
-        build-depends:
-            base >=4.6 && <5
-    else
-        build-depends:
-            base ==4.*
-    
-    if impl(ghc >=7.6.1)
-        cpp-options: -DNO_PRELUDE_CATCH
-    exposed-modules:
-        Shelly
-        Shelly.Lifted
-        Shelly.Pipe
-        Shelly.Unix
-    build-depends:
-        containers >=0.4.2.0,
-        time >=1.3 && <1.9,
-        directory >=1.1.0.0 && <1.4.0.0,
-        mtl >=2,
-        process >=1.0,
-        unix-compat <0.5,
-        system-filepath >=0.4.7 && <0.5,
-        system-fileio <0.4,
-        monad-control >=0.3.2 && <1.1,
-        lifted-base -any,
-        lifted-async -any,
-        exceptions >=0.6 && <0.9,
-        enclosed-exceptions -any,
-        text -any,
-        bytestring -any,
-        async -any,
-        transformers -any,
-        transformers-base -any
-    extensions: CPP
-    hs-source-dirs: src
-    other-modules:
-        Shelly.Base
-        Shelly.Find
-    ghc-options: -Wall
+Homepage:            https://github.com/yesodweb/Shelly.hs
+License:             BSD3
+License-file:        LICENSE
+Author:              Greg Weber, Petr Rockai
+Maintainer:          Greg Weber <greg@gregweber.info>
+Category:            Development
+Build-type:          Simple
+Cabal-version:       >=1.8
 
-executable  drain
-    main-is: drain.hs
+-- for the sdist of the test suite
+extra-source-files: test/src/*.hs
+                    test/examples/*.sh
+                    test/examples/*.hs
+                    test/data/zshrc
+                    test/data/nonascii.txt
+                    test/testall
+                    README.md
+                    ChangeLog.md
 
-executable  run-handles
-    main-is: run-handles.hs
+Library
+  Exposed-modules: Shelly, Shelly.Lifted, Shelly.Pipe, Shelly.Unix
+  other-modules:   Shelly.Base, Shelly.Find
+  hs-source-dirs: src
 
-executable  Color
-    main-is: color.hs
+  Build-depends:
+    containers                >= 0.4.2.0,
+    time                      >= 1.3 && < 1.9,
+    directory                 >= 1.1.0.0 && < 1.4.0.0,
+    mtl                       >= 2,
+    process                   >= 1.0,
+    unix-compat               < 0.5,
+    system-filepath           >= 0.4.7 && < 0.5,
+    system-fileio             < 0.4,
+    monad-control             >= 0.3.2 && < 1.1,
+    lifted-base,
+    lifted-async,
+    exceptions                >= 0.6 && < 0.9,
+    enclosed-exceptions,
+    text, bytestring, async, transformers, transformers-base
 
-test-suite  shelly-testsuite
-    
-    if flag(lifted)
-        cpp-options: -DLIFTED
-    type: exitcode-stdio-1.0
-    main-is: TestMain.hs
+  if impl(ghc >= 7.6.1)
     build-depends:
-        base >=4.6,
-        text >=0.11,
-        async -any,
-        bytestring >=0.10,
-        containers >=0.5.0.0,
-        directory >=1.1.0.0 && <1.4.0.0,
-        process >=1.1.0,
-        unix-compat <0.5,
-        system-filepath >=0.4.7 && <0.5,
-        system-fileio <0.4,
-        time >=1.3 && <1.9,
-        mtl >=2,
-        HUnit >=1.2,
-        hspec >=1.5,
-        transformers -any,
-        transformers-base -any,
-        monad-control -any,
-        lifted-base -any,
-        lifted-async -any,
-        enclosed-exceptions -any,
-        exceptions -any
-    extensions: OverloadedStrings ExtendedDefaultRules CPP
-    hs-source-dirs: src test/src
-    other-modules:
-        CopySpec
-        EnvSpec
-        FailureSpec
-        FindSpec
-        Help
-        LiftedSpec
-        MoveSpec
-        ReadFileSpec
-        RmSpec
-        RunSpec
-        Shelly
-        Shelly.Base
-        Shelly.Find
-        Shelly.Lifted
-        TestInit
-        WhichSpec
-        WriteSpec
-    ghc-options: -O2 -Wall -fwarn-tabs -funbox-strict-fields -threaded -fno-warn-unused-do-bind -fno-warn-type-defaults
+        base >= 4.6 && < 5
+  else
+    build-depends:
+      base >= 4 && < 5
+
+  ghc-options: -Wall
+
+  if impl(ghc >= 7.6.1)
+      CPP-Options: -DNO_PRELUDE_CATCH
+
+  extensions:
+    CPP
+
+source-repository head
+  type:     git
+  location: https://github.com/yesodweb/Shelly.hs
+
+Flag lifted
+   Description: run the tests against Shelly.Lifted
+   Default: False
+
+Test-Suite shelly-testsuite
+  type: exitcode-stdio-1.0
+  hs-source-dirs: src test/src
+  main-is: TestMain.hs
+  other-modules:
+    CopySpec
+    EnvSpec
+    FailureSpec
+    FindSpec
+    Help
+    LiftedSpec
+    MoveSpec
+    ReadFileSpec
+    RmSpec
+    RunSpec
+    Shelly
+    Shelly.Base
+    Shelly.Find
+    Shelly.Lifted
+    TestInit
+    WhichSpec
+    WriteSpec
+
+  ghc-options: -O2 -Wall -fwarn-tabs -funbox-strict-fields -threaded
+               -fno-warn-unused-do-bind -fno-warn-type-defaults
+
+
+  extensions: OverloadedStrings, ExtendedDefaultRules
+
+  if flag(lifted)
+     cpp-options: -DLIFTED
+
+  build-depends:
+    base                      >= 4.6,
+    text                      >= 0.11,
+    async,
+    bytestring                >= 0.10,
+    containers                >= 0.5.0.0,
+    directory                 >= 1.1.0.0 && < 1.4.0.0,
+    process                   >= 1.1.0,
+    unix-compat               < 0.5,
+    system-filepath           >= 0.4.7 && < 0.5,
+    system-fileio             < 0.4,
+    time                      >= 1.3 && < 1.9,
+    mtl                       >= 2,
+    HUnit                     >= 1.2,
+    hspec                     >= 1.5,
+    transformers,
+    transformers-base,
+    monad-control,
+    lifted-base,
+    lifted-async,
+    enclosed-exceptions,
+    exceptions
+
+  extensions:
+    CPP
+
+Flag build-examples
+   Description: build some example programs
+   Default: False
+   Manual: True
+
+-- demonstarated that command output in Shellish was not shown until after the command finished
+-- not necessary anymore
+Executable drain
+  hs-source-dirs: test/examples
+  main-is: drain.hs
+  if flag(build-examples)
+    buildable: True
+
+    build-depends: base                      >= 4.6
+                 , shelly
+                 , text
+
+    extensions:
+      CPP
+  else
+    buildable: False
+
+Executable run-handles
+  hs-source-dirs: test/examples
+  main-is: run-handles.hs
+  if flag(build-examples)
+    buildable: True
+
+    build-depends: base                      >= 4.6
+                 , shelly
+                 , text
+
+    extensions:
+      CPP
+  else
+    buildable: False
+
+Executable Color
+  hs-source-dirs: test/examples
+  main-is: color.hs
+  if flag(build-examples)
+    buildable: True
+
+    build-depends: base                      >= 4.6
+                 , process
+                 , shelly
+                 , text
+  else
+    buildable: False
diff --git a/src/Shelly.hs b/src/Shelly.hs
--- a/src/Shelly.hs
+++ b/src/Shelly.hs
@@ -1396,7 +1396,10 @@
 hasExt :: Text -> FilePath -> Bool
 hasExt = flip hasExtension
 
--- | Run a Sh computation and collect timing  information.
+-- | Run a Sh computation and collect timing information.
+--   The value returned is the amount of _real_ time spent running the computation
+--   in seconds, as measured by the system clock.
+--   The precision is determined by the resolution of `getCurrentTime`.
 time :: Sh a -> Sh (Double, a)
 time what = sub $ do
   trace "time"
