it is just

  [hello].
  %or
  ['hello.pl'].
  %or
  ["hello.pl"].

the '.' has syntactic meaning outside of quotes.

now to demonstrate file i/o:

we make a file hello.pl that has

  :- use_module(library(readutil)).

  readmyfile(Filename) :-
    open(Filename,read, Stream),
    read_line_to_string(Stream,Input),
    write("The line is:"), nl,
    write(Input), nl,
    close(Stream),
    %or slurp the whole thing
    read_file_to_string(Filename,WholeFile,[encoding(text)]),
    %lets use the formatted output predicate
    format("The file ~s has the following contents ~n~s ~n",[Filename,WholeFile]).

then launch swi and

  ?- [hello].
  true.

  ?- readmyfile('hello.pl').
  The line is:
  :- use_module(library(readutil)).
  The file hello.pl has the following contents 
  ...
  ...
  ...
  true.