ref: a351bcdccdf5a4273bc8dc3360a48fbb8b8aa9ea
dir: /src/before.c/
#include <u.h>
#include <libc.h>
void
main(int, char*[])
{
int fd;
fd = create("afile", OWRITE, 0644);
write(fd, "hello\n", 6);
if (fork() == 0)
write(fd, "child\n", 6);
else
write(fd, "dad\n", 4);
close(fd);
exits(nil);
}