str2val
pnum = str2val(optarg, "proto number", 1, 255);
int str2val(const char *, const char *, int, int);
first_ttl = str2val(optarg, "first ttl", 1, 255);
max_ttl = str2val(optarg, "max ttl", 1, 255);
requestPort = (u_short)str2val(optarg, "port",
nprobes = str2val(optarg, "nprobes", 1, -1);
tos = str2val(optarg, "tos", 0, 255);
waittime = str2val(optarg, "wait time",
pausemsecs = str2val(optarg, "pause msecs",
packlen = str2val(argv[optind + 1],