#!/bin/sh awk ' { year = $1 if (prevyear) { diff = year - prevyear if (diff < 10) { single_digit_years += diff } else { single_digit_years += 9 two_digit_years += diff - 9 } } prevyear = year } END { printf "%d single-digit years, %d two-digit years\n", \ single_digit_years, two_digit_years } ' <<'EOF' 701 704 708 715 717 724 729 749 749 757 765 767 770 781 782 806 810 824 834 848 851 854 857 859 877 885 889 898 901 923 931 938 947 957 961 964 968 970 973 976 978 983 985 987 988 990 995 999 1004 1012 1017 1021 1024 1028 1037 1040 1044 1046 1053 1058 1065 1069 1074 1077 1081 1084 1087 1094 1096 1097 1099 1104 1106 1108 1110 1113 1118 1120 1124 1126 1131 1132 1135 1141 1142 1144 1145 1151 1154 1156 1159 1160 1161 1163 1165 1166 1169 1171 1175 1177 1181 1182 1184 1185 1190 1199 1201 1204 1206 1207 1211 1213 1219 1222 1224 1225 1227 1229 1232 1233 1234 1235 1238 1239 1240 1243 1247 1249 1256 1257 1259 1260 1261 1264 1275 1278 1288 1293 1299 1302 1303 1306 1308 1311 1312 1317 1319 1321 1324 1326 1329 1331 1334 1336 1340 1346 1370 1372 1375 1381 1384 1332 1334 1338 1342 1345 1350 1352 1356 1361 1362 1368 1375 1379 1381 1384 1387 1389 1390 1394 1428 1429 1441 1444 1449 1452 1455 1457 1460 1466 1467 1469 1487 1489 1492 1501 1504 1521 1528 1532 1555 1558 1570 1573 1592 1596 1615 1624 1644 1648 1652 1655 1658 1661 1673 1681 1684 1688 1704 1711 1716 1736 1741 1744 1748 1751 1764 1772 1781 1789 1801 1804 1818 1830 1844 1848 1854 1860 1861 1864 1865 1868 1912 1926 1989 2019 EOF