--- /dev/null
+#!/bin/bash
+# Desc: Template to report seconds until beginning of next day
+# Author: Steven Baltaktei Sandoval; License: GPLv3+
+
+#==BEGIN Define script parameters==
+#===BEGIN Declare local script functions===
+yell() { echo "$0: $*" >&2; } # Yell, Die, Try Three-Fingered Claw technique; # Ref/Attrib: https://stackoverflow.com/a/25515370
+die() { yell "$*"; exit 111; }
+try() { "$@" || die "cannot $*"; }
+timeUntilNextDay(){
+ # Desc: Report seconds until next day.
+ # Output: stdout: integer seconds until next day
+ # Output: exit code 0 if stdout > 0; 1 if stdout = 0; 2 if stdout < 0
+ # Usage: timeUntilNextDay
+ # Usage: if ! myTTL="$(timeUntilNextDay)"; then yell "ERROR in if statement"; exit 1; fi
+ local returnState
+ TIME_CURRENT="$(date --iso-8601=seconds)" ; # Produce `date`-parsable current timestamp with resolution of 1 second.
+ TIME_CURRENT_SHORT="$(date -d "$TIME_CURRENT" +%Y%m%dT%H%M%S%z)" # Produce separator-less current timestamp with resolution 1 second.
+ DATE_CURRENT="$(date -d "$TIME_CURRENT" --iso-8601=date)" ; # Produce `date`-parsable current timestamp with resolution of 1 day.
+ DATE_CURRENT_SHORT="$(date -d "$TIME_CURRENT" +%Y%m%d)" ; # Produce separator-less current timestamp with resolution 1 day.
+ DATE_TOMORROW="$(date -d "$TIME_CURRENT next day" --iso-8601=date)" ; # Produce timestamp of tomorrow's date (res. 1 day).
+ TIME_NEXT_DAY="$(date -d "$DATE_TOMORROW" --iso-8601=seconds)" ; # Produce `date`-parsable timestamp of closest next day (res. 1 second).
+ SECONDS_UNTIL_NEXT_DAY="$(( $(date +%s -d "$TIME_NEXT_DAY") - $(date +%s -d "$TIME_CURRENT") ))" ; # Calculate seconds until closest future midnight (res. 1 second).
+ if [[ "$SECONDS_UNTIL_NEXT_DAY" -gt 0 ]]; then
+ returnState="true";
+ elif [[ "$SECONDS_UNTIL_NEXT_DAY" -eq 0 ]]; then
+ returnState="WARNING_ZERO";
+ yell "WARNING:Reported time until next day exactly zero.";
+ elif [[ "$SECONDS_UNTIL_NEXT_DAY" -lt 0 ]]; then
+ returnState="WARNING_NEGATIVE";
+ yell "WARNING:Reported time until next day is negative.";
+ fi
+
+ try echo "$SECONDS_UNTIL_NEXT_DAY"; # Report
+
+ #===Determine function return code===
+ if [[ "$returnState" = "true" ]]; then
+ return 0;
+ elif [[ "$returnState" = "WARNING_ZERO" ]]; then
+ return 1;
+ elif [[ "$returnState" = "WARNING_NEGATIVE" ]]; then
+ return 2;
+ fi
+} # Report seconds until next midnight
+#===END Declare local script functions===
+#==END Define script parameters==
+
+
+#==BEGIN sample code==
+try echo "Time until next day (seconds):$(timeUntilNextDay)" # simple report
+
+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.
+#==END sample code==