If format starts with '*l' then returns the next line in the File. The end-of-line character is skipped.

If format starts with '*a' then returns all the remaining contents of the File.

If no data is available, then an error is raised, except if File is in quiet() mode where it then returns nil.

Because Torch is more precised on number typing, the Lua format '*n' is not supported: instead use one of the number read methods.