1bash_command(Command, Output) :-
    2	process_create(path(bash),
    3		       ['-c', Command],
    4		       [stdout(pipe(Out))]),
    5	read_string(Out, _, Output),
    6	close(Out).

   10grep(File, Pattern, Lines) :-
   11	process_create(path(grep), [ Pattern, file(File) ],
   12		       [ stdout(pipe(Out))
   13		       ]),
   14	read_lines(Out, Lines).
   15
   16read_lines(Out, Lines) :-
   17	read_line_to_codes(Out, Line1),
   18	read_lines(Line1, Out, Lines).
   19
   20read_lines(end_of_file, _, []) :- !.
   21read_lines(Codes, Out, [Line|Lines]) :-
   22	atom_codes(Line, Codes),
   23	read_line_to_codes(Out, Line2),
   24	read_lines(Line2, Out, Lines)