diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,8 @@
 # Revision history for simple-cmd
 
+## 0.1.3.1
+- sudo: ignored for root or when no sudo installed
+
 ## 0.1.3 -- 2019-02-20
 - gitDiffQuiet
 - fix rwGitDir regexp
diff --git a/SimpleCmd.hs b/SimpleCmd.hs
--- a/SimpleCmd.hs
+++ b/SimpleCmd.hs
@@ -49,11 +49,15 @@
 #else
 import Control.Applicative ((<$>))
 #endif
+import Control.Monad (when)
 
 import Data.List (stripPrefix)
-import Data.Maybe (fromMaybe)
+import Data.Maybe (isNothing, fromMaybe)
 
+import System.Directory (findExecutable)
 import System.Exit (ExitCode (..))
+import System.IO (hPutStrLn, stderr)
+import System.Posix.User (getEffectiveUserID)
 import System.Process (readProcess, readProcessWithExitCode, rawSystem)
 
 removeTrailingNewline :: String -> String
@@ -196,7 +200,15 @@
 sudo :: String -- ^ command
      -> [String] -- ^ arguments
      -> IO ()
-sudo c args = cmdlog "sudo" (c:args)
+sudo c args = do
+  uid <- getEffectiveUserID
+  sd <- if uid == 0
+    then return Nothing
+    else findExecutable "sudo"
+  let noSudo = isNothing sd
+  when (uid /= 0 && noSudo) $
+    hPutStrLn stderr "'sudo' not found"
+  cmdlog (fromMaybe c sd) (if noSudo then args else c:args)
 
 -- | Combine two strings with a single space
 infixr 4 +-+
diff --git a/SimpleCmd/Git.hs b/SimpleCmd/Git.hs
--- a/SimpleCmd/Git.hs
+++ b/SimpleCmd/Git.hs
@@ -1,3 +1,7 @@
+{-|
+Some wrappers for git commands.
+-}
+
 module SimpleCmd.Git (
   git,
   git_,
diff --git a/SimpleCmd/Rpm.hs b/SimpleCmd/Rpm.hs
--- a/SimpleCmd/Rpm.hs
+++ b/SimpleCmd/Rpm.hs
@@ -1,3 +1,7 @@
+{-|
+This Rpm module currently only provides @rpmspec@.
+-}
+
 module SimpleCmd.Rpm (
   rpmspec
   ) where
diff --git a/simple-cmd.cabal b/simple-cmd.cabal
--- a/simple-cmd.cabal
+++ b/simple-cmd.cabal
@@ -1,5 +1,5 @@
 name:                simple-cmd
-version:             0.1.3
+version:             0.1.3.1
 synopsis:            Simple String-based process commands
 description:
             Thin wrappers over System.Process (readProcess,
@@ -28,7 +28,7 @@
   exposed-modules:     SimpleCmd,
                        SimpleCmd.Git,
                        SimpleCmd.Rpm
-  build-depends:       base < 5, directory, filepath, process
+  build-depends:       base < 5, directory, filepath, process, unix
   default-language:    Haskell2010
   default-extensions:  CPP
   ghc-options:   -fwarn-missing-signatures -Wall