Pádraig Brady wrote: > It's probably useful to add this functionality to all coreutil filters. > I still need to be convinced that glibc is not the correct place for this. > If it was there then any users of stdio could be controlled.
It has been said before in previous threads but I want to re-state that this is possible in a very simple and general way with the LD_PRELOAD facility: $ echo '__attribute__((constructor)) void f() { setvbuf (stdout, NULL, _IOLBF, 0); }' | \ gcc -include stdio.h -x c - -fPIC -shared -o linebuf.so $ ( while true; do echo "foo"; sleep 1; done ) | LD_PRELOAD=./linebuf.so grep foo | cat foo foo foo ... # immediate output Brian