/usr/lib/hugs/packages/base/System/Cmd.hs is in libhugs-base-bundled 98.200609.21-5.3ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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-- |
-- Module : System.Cmd
-- Copyright : (c) The University of Glasgow 2001
-- License : BSD-style (see the file libraries/base/LICENSE)
--
-- Maintainer : libraries@haskell.org
-- Stability : provisional
-- Portability : portable
--
-- Executing an external command.
--
-----------------------------------------------------------------------------
module System.Cmd
( system, -- :: String -> IO ExitCode
rawSystem, -- :: FilePath -> [String] -> IO ExitCode
) where
import Prelude
import System.Exit ( ExitCode )
import Hugs.System
-- ---------------------------------------------------------------------------
-- system
{-|
Computation @system cmd@ returns the exit code
produced when the operating system processes the command @cmd@.
This computation may fail with
* @PermissionDenied@: The process has insufficient privileges to
perform the operation.
* @ResourceExhausted@: Insufficient resources are available to
perform the operation.
* @UnsupportedOperation@: The implementation does not support
system calls.
On Windows, 'system' is implemented using Windows's native system
call, which ignores the @SHELL@ environment variable, and always
passes the command to the Windows command interpreter (@CMD.EXE@ or
@COMMAND.COM@), hence Unixy shell tricks will not work.
-}
{-|
The computation @'rawSystem' cmd args@ runs the operating system command
@cmd@ in such a way that it receives as arguments the @args@ strings
exactly as given, with no funny escaping or shell meta-syntax expansion.
It will therefore behave more portably between operating systems than 'system'.
The return codes and possible failures are the same as for 'system'.
-}
rawSystem :: String -> [String] -> IO ExitCode
-- crude fallback implementation: could do much better than this under Unix
rawSystem cmd args = system (unwords (map translate (cmd:args)))
translate :: String -> String
translate str = '\'' : foldr escape "'" str
where escape '\'' = showString "'\\''"
escape c = showChar c
|