I am really struggling with Haskell I/O. 

I have written a mergesort program and as an input to that program I want to use a file containing a list of 1000 integers. Let's say the contents of the file look like this

[120, 400, 500 , 20, 100 ..] 

How can I achieve that? I am trying to write a main function that takes the file as an input and passes the list to my mergesort function.. 

Regards

Awsaf Rahman