Thanks for your comment. I know these options. But they don't solve the task of parsing log files. Most probably, I haven't been very specific and some explanations are required. A log file could be:

2017-09-04 22:02:14.123 INFO: Some log message having param1=value1
2017-09-04 22:02:14.349 DEBUG: Multiline log entry
Some extended logging:
debug {
    param1 value1
    param2 value2
}
2017-09-04 22:02:14.658 INFO: Another log message param2=value2
[download]

If we need all entries containing some specific strings (let say value1), it is difficult to parse the file with -00. That's why I (re)invented a bike. :)