#include <unistd.h>
-void do_exec(int skip, int ac, char *av[]) {
+static void do_exec(int skip, int ac, char *av[]) {
int i;
+ if (skip >= ac) {
+ fprintf(stderr, "nothing to exec\n");
+ exit(EXIT_FAILURE);
+ }
+
for (i=0;i<ac-skip;i++) {
av[i] = av[i+skip];
}