#include <errno.h>
#include <stdio.h>

#include <err.h>
#include <fcntl.h>
#include <sys/types.h>
#include <unistd.h>

char b[4096];
ssize_t r, w;
size_t i;

#define A(x, l, e) if ((x) < 0) if (errno == EAGAIN) goto l; else goto e; if (!(x)) goto e; else

int
main(int f, char **v)
{
	if (f) goto E; if (!*v) goto F;
	if ((f = open(*v, O_RDONLY)) < 0) err(1, "open(`%s')", *v);
R:	r = read(f, b, sizeof(b));
	A(r, R, E);
W:	w = write(1, b, r);
	A(w, W, R);
	r -= (i = w);
	while (i < r+w) b[i-w] = b[i];
	goto W;
E:	f && close(f); main(0, ++v);
F:	;
}