i see the following behavior which differs from one i used to have at linux machines:
tail -F path_to_file | grep 'blabla'
instead of starting to listen at the end of file and output the corresponding content that arrives after command execution, the file is searched from the beginning and all results are shown. only once the end of file is reached, script starts to behave as expected.
I was able to replicate this. What I did was I just backed-up the previous file (log file) and started with a clean one so that it will not read the entire file containing previous logs.
In UNIX, the tail command reads the last parts of the file without having to echo the entire file on terminal.
Seems there are problems with version 5.3.0 of tail
Read this http://sourceforge.net/p/gnuwin32/bugs/242/
I had ended replacing tail with version 2.1 and everything works fine