util.h

   1 #define MIN(a, b)               ((a) < (b) ? (a) : (b))
   2
   3 int file_size(int fd);
   4 int xread(int fd, char *buf, int len);
   5 int xwrite(int fd, char *buf, int len);
   6 void exec_file(char *filename, char **args);
   7 void exec_pipe(char *file, char **argv, char *s, int len);