#include /* file descriptor --- from */ #define STDIN_FILENO 0 /* Standard input. */ #define STDOUT_FILENO 1 /* Standard output. */ #define STDERR_FILENO 2 /* Standard error output. */ main() { int n; char buf[BUFSIZ]; while((n = read(STDIN_FILENO, buf, sizeof buf)) > 0 ) { write(STDOUT_FILENO, buf, n); } exit(0); }