Library to support operations related to the program execution path,
i.e., environment variable PATH.
          
Author: Michael Hanus
Version: November 2018
| dirsInPath
                  ::  IO [String]Returns the list of the directories of the environment variable PATH. | 
| fileInPath
                  ::  String -> IO BoolChecks whether a file exists in one of the directories of the environment variable PATH. | 
| getFileInPath
                  ::  String -> IO (Maybe String)Checks whether a file exists in one of the directories of the environment variable PATHand returns its absolute path,
otherwise returnsNothing. | 
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                      Returns the list of the directories of the environment variable  | 
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                      Checks whether a file exists in one of the directories
of the environment variable  | 
| 
                       
                      Checks whether a file exists in one of the directories
of the environment variable  |