How to get shell echo in Prolog variables

General
15

This uses a thread, to prevent hanging:

run_sh_command(StrCmd, OutputLines, ErrorLines, ExitCode) :-
    run_command([sh, '-ce', StrCmd], OutputLines, ErrorLines, ExitCode).

run_command(LstCmd, OutputLines, ErrorLines, ExitCode) :-
    LstCmd = [ExeName|Args],
    setup_call_cleanup(
        message_queue_create(ErrorQueue),
        setup_call_cleanup(
            process_create(
                path(ExeName), Args, [
                    process(PID),
                    stdout(pipe(OutputStream)),
                    stderr(pipe(ErrorStream))
                ]   
            ),
            (   thread_create(
                    (   read_stream_lines(ErrorStream, ErrorLines),
                        thread_send_message(ErrorQueue, ErrorLines)
                    ),
                    ThreadId
                ),
                read_stream_lines(OutputStream, OutputLines),
                process_wait(PID, ExitCode),
                thread_join(ThreadId),
                thread_get_message(ErrorQueue, ErrorLines)
            ),  
            (   close(OutputStream),
                close(ErrorStream)
            )   
        ),
        message_queue_destroy(ErrorQueue)
    ). 

read_stream_lines(Stream, Lines) :-
    read_line_to_codes(Stream, Line1),
    read_stream_lines_(Line1, Stream, Lines).

read_stream_lines_(end_of_file, _, Lines) :-
    !,
    Lines = [].
read_stream_lines_(Codes, Stream, [Line|Lines]) :-
    atom_codes(Line, Codes),
    read_line_to_codes(Stream, Line2),
    read_stream_lines_(Line2, Stream, Lines).