while (sh = getusershell()) {
while ((sh = getusershell()) != NULL) {
ok_shell(name)	char *name;{	char *p, *sh;	setusershell();	while (sh = getusershell()) {		if (!strcmp(name, sh))			return (name);		/* allow just shell name, but use "real" path */		if ((p = strrchr(sh, '/')) && strcmp(name, p + 1) == 0)			return (sh);	}	return (NULL);}