def filter_by_program(self, prg, opFile):
        """
        parse the log files and extract entries from all 
        logfiles to one file per program (program is the 
        2nd to last entry each logfile)
        """
        log_1 = open(self.process_file, 'r')
        log_2 = open(self.command_file, 'r')
        log_3 = open(self.result_file, 'r')
        log_4 = open(self.source_file, 'r')
        
        with open(opFile, 'a') as f:
            for line in log_1:
                if prg in line:
                    f.write('PROCESS, ' + line)
            for line in log_2:
                if prg in line:
                    f.write('COMMAND, ' + line)
            for line in log_3:
                if prg in line:
                    f.write('RESULT, ' + line)
            for line in log_4:
                if prg in line:
                    f.write('SOURCE, ' + line)
                    
        log_1.close()
        log_2.close()
        log_3.close()
        log_4.close()
parse the log files and extract entries from all 
        logfiles to one file per program (program is the 
        2nd to last entry each logfile)