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Add grep command #1

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Add grep command #1

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20 changes: 20 additions & 0 deletions src/grep.hs
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module Main where

import Data.List (isInfixOf)
import System.Environment (getArgs)

-- grep
main :: IO()
main = do
args <- getArgs

--Get the search pattern from the first argument
let pattern = head args

--Read all file names on command line
fileContents <- mapM readFile $ tail args

let lineContents = concat $ map lines fileContents
let selection = filter (isInfixOf pattern) lineContents

mapM_ putStrLn selection