# File app/bin/grep.rb, line 60
        def process_one_file(path)
                option = 0
                option |= Regexp::MULTILINE if @multiline
                option |= Regexp::IGNORECASE if @ignore
                @regexp = Regexp.new(@pattern, option)
                
                @match_line_count = 0
                @match_string_count = 0
                
                text = read_file(path)
                pos_arr = matching(text)
                puts_matched_lines(text, pos_arr)
                puts_summary(path)
        end