How do I exit tail --follow on ERROR or FATAL log level

Question

I tail -f the log file of one of my services, but I would like to automatically stop my tail process once my logger has printed any content starting with OR containing ERROR or FATAL.

How can I achieve this?

Answer 1

To terminate tail -f immediately after the output has a line containing ERROR or FATAL, try:

tail -f file.log | awk '{print} /ERROR|FATAL/{exit}'

Example

$ cat file.log 
abc
def
ghi
ERROR
jkl
mno
pqr
$ tail -f file.log | awk '{print} /ERROR|FATAL/{exit}'
abc
def
ghi
ERROR