Mine

import System (getArgs)
import System.IO
import System.Exit (exitFailure)

checkArgs = do
	args <- getArgs
	case args of
		[ file, offset ] -> ( file, offset )
		_ -> do
			putStrLn "Syntax: powercat <file> <offset>"
			exitFailure

doCat file offset = do
	handle <- openFile file ReadMode
	hSeek handle AbsoluteSeek offset
	hGetContents handle >>= putStr

main = do
	args <- checkArgs
	doCat $ fst args $ read $ snd args