How to 'grep' a continuous stream?

Question

Is that possible to use grep on a continuous stream?

What I mean is sort of a tail -f command, but with grep on t

Answer 1

If you want to find matches in the entire file (not just the tail), and you want it to sit and wait for any new matches, this works nicely:

tail -c +0 -f  | grep --line-buffered 

The -c +0 flag says that the output should start 0 bytes (-c) from the beginning (+) of the file.