Executing a system command in Haskell

How could I execute a system command such as cp somefile somedestination in Haskell?

Something like an os.Exec.

The Haskell 98 standard provides:

System.system :: String
              -> IO GHC.IO.Exception.ExitCode

which executes a command.

The new System.Process library is more useful though, allowing for portable input/output redirection and so forth.

import System.Process

main = callCommand "cp somefile somedestination"

just works, but you may prefer other functions from the System.Process module.

I'm not a haskell buff, but this may be what you're looking for

If you do this sort of thing a lot then it's worth having a look at http://hackage.haskell.org/package/HSH.