Sorry this was done in Windows 10, so the file input files include \r\n for each newline. If you try this out in linux, you need to accommodate for that.
To run, you need erlang : http://erlang.org/
Simply run the compile command on each file in the main directory,
1> c(day1). {ok, day1}
And run the corresponding day using run() to get the result.
2> day1:run().