unitproc/bkt-timeUntilNextDay

   1 #!/bin/bash
   2 # Desc: Template to report seconds until beginning of next day
   3
   4 #==BEGIN Define script parameters==
   5 #===BEGIN Declare local script functions===
   6 yell() { echo "$0: $*" >&2; } # Yell, Die, Try Three-Fingered Claw technique; # Ref/Attrib: https://stackoverflow.com/a/25515370
   7 die() { yell "$*"; exit 111; }
   8 try() { "$@" || die "cannot $*"; }
   9 timeUntilNextDay(){
  10     # Desc: Report seconds until next day.
  11     # Version: 1.0.3
  12     # Output: stdout: integer seconds until next day
  13     # Output: exit code 0 if stdout > 0; 1 if stdout = 0; 2 if stdout < 0
  14     # Usage: timeUntilNextDay
  15     # Usage: if ! myTTL="$(timeUntilNextDay)"; then yell "ERROR in if statement"; exit 1; fi
  16     # Depends: date 8, echo 8, yell, try
  17
  18     local returnState timeCurrent timeNextDay secondsUntilNextDay
  19     timeCurrent="$(date --iso-8601=seconds)" ; # Produce `date`-parsable current timestamp with resolution of 1 second.
  20     timeNextDay="$(date -d "$timeCurrent next day" --iso-8601=date)"; # Produce timestamp of beginning of tomorrow with resolution of 1 second.
  21     secondsUntilNextDay="$(( $(date +%s -d "$timeNextDay") - $(date +%s -d "$timeCurrent") ))" ; # Calculate seconds until closest future midnight (res. 1 second).
  22     if [[ "$secondsUntilNextDay" -gt 0 ]]; then
  23         returnState="true";
  24     elif [[ "$secondsUntilNextDay" -eq 0 ]]; then
  25         returnState="warning_zero";
  26         yell "WARNING:Reported time until next day exactly zero.";
  27     elif [[ "$secondsUntilNextDay" -lt 0 ]]; then
  28         returnState="warning_negative";
  29         yell "WARNING:Reported time until next day is negative.";
  30     fi
  31
  32     try echo "$secondsUntilNextDay"; # Report
  33
  34     # Determine function return code
  35     if [[ "$returnState" = "true" ]]; then
  36         return 0;
  37     elif [[ "$returnState" = "warning_zero" ]]; then
  38         return 1;
  39     elif [[ "$returnState" = "warning_negative" ]]; then
  40         return 2;
  41     fi
  42 } # Report seconds until next day
  43 #===END Declare local script functions===
  44 #==END Define script parameters==
  45
  46
  47 #==BEGIN sample code==
  48 try echo "Time until next day (seconds):$(timeUntilNextDay)" # simple report
  49
  50 if ! myTTL="$(timeUntilNextDay)"; then yell "ERROR in if statement for myTTL:$myTTL"; exit 1; fi # Use of exit code to exit early if time <= 0.
  51 #==END sample code==
  52
  53 # Author: Steven Baltaktei Sandoval
  54 # License: GPLv3+