Haskell: withCurrentDirectory: Work with given directory

By using withCurrentDirectory function, you can run an IO action with the given working directory and restore the original working directory afterwards. Following is the signature of withCurrentDirectory function.

Prelude System.Directory> :t withCurrentDirectory

withCurrentDirectory :: FilePath -> IO a -> IO a

Example 1

import System.IO
import System.Directory

main = do
    currentDir <- getCurrentDirectory
    putStrLn $ "Curren working directory is : " ++ currentDir

    putStrLn "Enter directory name"
    dir <- getLine

    result <- withCurrentDirectory dir getCurrentDirectory
    putStrLn $ "Curren working directory is changed to  : " ++ result

    currentDire <- getCurrentDirectory
    putStrLn $ "Curren working directory is changed back to: " ++ currentDir

$ runghc DirectoryUtil.hs 
Curren working directory is : /Users/harikrishna_gurram/study1/Haskell/programs
Enter directory name
/Users
Curren working directory is changed to  : /Users
Curren working directory is changed back to: /Users/harikrishna_gurram/study1/Haskell/programs
localhost:programs harikrishna_gurram$ 

Example 2

DirectoryUtil.hs

import System.IO
import System.Directory

listContents = 
    do
      currentDir <- getCurrentDirectory
      putStrLn $ "Current working directory is changed to :" ++ currentDir
      listDirectory currentDir

main = do
    currentDir <- getCurrentDirectory
    putStrLn $ "Current working directory is : " ++ currentDir

    putStrLn "Enter directory name"
    dir <- getLine

    result <- withCurrentDirectory dir listContents
    putStrLn $ "Contents of given directory " ++ (show result)

    currentDire <- getCurrentDirectory
    putStrLn $ "Current working directory is changed back to : " ++ currentDir

$ runghc DirectoryUtil.hs 
Current working directory is : /Users/harikrishna_gurram/study1/Haskell/programs
Enter directory name
/Users
Current working directory is changed to :/Users
Contents of given directory [".localized","harikrishna_gurram","Shared"]
Current working directory is changed back to : /Users/harikrishna_gurram/study1/Haskell/programs

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