unitproc/bkt-list_days_of_year.sh

   1 #!/usr/bin/env bash
   2
   3 yell() { echo "$0: $*" >&2; } # print script path and all args to stderr
   4 die() { yell "$*"; exit 111; } # same as yell() but non-zero exit status
   5 try() { "$@" || die "cannot $*"; } # runs args as command, reports args if command fails
   6 list_days_of_year() {
   7     # Desc: Lists days of year in ISO-8601 YYYY-mm-dd format
   8     # Usage: script.sh [str year]
   9     # Input: arg1: year (4 digit gregorian calendar year)
  10     # Output: stdout: iso-8601 dates (newline delimited)
  11     # Depends: bash (5.1.16), GNU Coreutils (8.32; date, printf)
  12     # Version: 0.0.1
  13     # Ref/Attrib: [1] Linux Bash: How to print leading zeroes on a variable https://bytefreaks.net/gnulinux/bash/linux-bash-how-to-print-leading-zeroes-on-a-variable
  14
  15     # Check arg
  16     ## Validate argument count
  17     if [[ $# -ne 1 ]]; then die "FATAL:Invalid number of arguments:$#"; fi;
  18     year="$1";
  19
  20     ## Validate arg is a 4-digit year
  21     pattern='^[0-9]{4}$';
  22     if [[ ! $year =~ $pattern ]]; then die "FATAL:Not a 4-digit year."; fi;
  23     if [[ ! $year -gt 1582 ]]; then die "FATAL:Not a gregorian calendar year."; fi;
  24
  25     yyyy=$year;
  26     for (( month = 1; month <= 12; month++ )); do
  27         mm="$(printf %02d "$month")"; # two-digit month; See [1]
  28         #yell "DEBUG:mm:$mm";
  29         for (( day = 1; day <= 31; day++ )); do
  30             dd="$(printf %02d "$day")"; # two-digit day; See [1]
  31             #yell "DEBUG:dd:$dd";
  32             date_iso8601="$yyyy-$mm-$dd";
  33             if date --date="$date_iso8601" 1>/dev/random 2>&1; then
  34                 printf "%s\n" "$date_iso8601";
  35             fi;
  36         done;
  37     done;
  38 }; # iso-8601 dates (yyyy-mm-dd) to stdout
  39
  40 # Test
  41 wc -l < <(list_days_of_year 1583); # should report 365 lines
  42 wc -l < <(list_days_of_year 2023); # should report 365 lines
  43 wc -l < <(list_days_of_year 2024); # should report 366 lines (leap year)
  44 wc -l < <(list_days_of_year 2025); # should report 365 lines
  45 wc -l < <(list_days_of_year 9999); # should report 365 lines
  46
  47 # Author: Steven Baltakatei Sandoval
  48 # License: GPLv3+
  49
  50 # Ref/Attrib
  51 # # date (GNU coreutils) 8.32
  52 # # Copyright (C) 2020 Free Software Foundation, Inc.
  53 # # License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
  54 # # This is free software: you are free to change and redistribute it.
  55 # # There is NO WARRANTY, to the extent permitted by law.
  56
  57 # # Written by David MacKenzie.
  58
  59
  60 # # printf (GNU coreutils) 8.32
  61 # # Copyright (C) 2020 Free Software Foundation, Inc.
  62 # # License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
  63 # # This is free software: you are free to change and redistribute it.
  64 # # There is NO WARRANTY, to the extent permitted by law.
  65
  66 # # Written by David MacKenzie.
  67
  68
  69 # # GNU bash, version 5.1.16(1)-release (x86_64-pc-linux-gnu)
  70 # # Copyright (C) 2020 Free Software Foundation, Inc.
  71 # # License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
  72
  73 # # This is free software; you are free to change and redistribute it.
  74 # # There is NO WARRANTY, to the extent permitted by law.