使用AWK在shell中生成日历小程序

#  在shell中生成日历#  使用方式#  awk -f thisFile +2017#  awk -f thisFile +2017.10#  awk -f thisFile +2017.10.10#function whichWeek(y, m, d, s) {    s = 0    if (((y%4 == 0) && (y%100 != 0)) || (y%400 == 0)) if (M[2] == 28) M[2]++    if (y>0) s += --y + int(y/4) - int(y/100) + int(y/400)    while (m > 1) s += M[--m]    return (s+d)%7}function printCalendar(y, m, d, nowWeek, i){  printf("%d%s %d%s/n", y, "年", m, "月")  print "日 一 二 三 四 五 六 "  printf("%s", repeat(" ", ((nowWeek+1)%7)*3))  for (i=1; i<=M[m]; i++) {    if ((nowWeek+i) % 7 != 6) {      printf("%2d ", i)    } else {      printf("%2d /n", i)    }  }  print "/n"}function repeat(flag, time, i, str){  for (i=0; i<time; i++) {    str = str flag  }  return str}function option(opt) {  if (ARGC > 1 && ARGV[1] ~ /^/+.*$/) {    print ARGC, ARGV[1]    opt = substr(ARGV[1], 2)    delete ARGV[1]  }  return opt}BEGIN {  M[1] = 31  M[2] = 28  M[3] = 31  M[4] = 30  M[5] = 31  M[6] = 30  M[7] = 31  M[8] = 31  M[9] = 30  M[10] = 31  M[11] = 30  M[12] = 31  W[0] = "日"  W[1] = "一"  W[2] = "二"  W[3] = "三"  W[4] = "四"  W[5] = "五"  W[6] = "六"  split(option(), date, ".")  nowWeek = whichWeek(date[1]+0, date[2]+0, date[3]+0)  if (date[3] != "") {    print "星期" W[nowWeek]  } else if (date[2] != "") {    printCalendar(date[1]+0, date[2]+0, M[date[2]], nowWeek)  } else {    for (j=1; j<=12; j++) {      printCalendar(date[1]+0, j, M[i], whichWeek(date[1]+0, j, 0))    }  }}