On Mon, Jul 14, 2014 at 10:31:27PM -0400, Doug McIlroy wrote: It really depends on what you want. That buffering is a big win for some use cases. Even on today's processors reading a byte at a time via read(2) is costly. Like 5000x more costly on the laptop I'm typing on: calvin:~/tmp lmdd opat=1 move=100m of=XXX 104.8576 MB in 0.1093 secs, 959.5578 MB/sec calvin:~/tmp time a.out fd < XXX real 0m14.754s user 0m1.516s sys 0m13.201s calvin:~/tmp time a.out stdio < XXX real 0m0.003s user 0m0.000s sys 0m0.000s calvin:~/tmp bc 14.754/.003 4918.00000000000000000000 #include <stdio.h> #include <string.h> #include <stdlib.h> #define unless(x) if (!(x)) #define streq(a, b) !strcmp(a, b) main(int ac, char **av) { char c; unless (ac == 2) exit(1); if (streq(av[1], "stdio")) { while ((c = fgetc(stdin)) != EOF) ; } else { while (read(0, &c, 1) == 1) ; } exit(0); }