How do I read the entire content of a given file into a string?

Question

My given file /path/file.txt contains for example the following:

Hello World!
Try to read me.

How can I read the entire content into one single string inside my code?
For this specific example, the string should look like this:

"Hello World!\nTry to read me."

Answer 1

If you don't want to use Core, the following works with functions from the built-in Pervasives module:

let read_whole_file filename =
    let ch = open_in filename in
    let s = really_input_string ch (in_channel_length ch) in
    close_in ch;
    s