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

Turn on grep's line buffering mode when using BSD grep (FreeBSD, Mac OS X etc.)

tail -f file | grep --line-buffered my_pattern

You don't need to do this for GNU grep (used on pretty much any Linux) as it will flush by default (YMMV for other Unix-likes such as SmartOS, AIX or QNX).