+} # Get YYYYmmddTHHMMSS±zzzz
+dateShort(){
+ # Desc: Date without separators (YYYYmmdd)
+ # Usage: dateShort
+ # Output: stdout: date (ISO-8601, no separators)
+ local TIME_CURRENT DATE_CURRENT_SHORT
+ TIME_CURRENT="$(date --iso-8601=seconds)" ; # Produce `date`-parsable current timestamp with resolution of 1 second.
+ DATE_CURRENT_SHORT="$(date -d "$TIME_CURRENT" +%Y%m%d)"; # Produce separator-less current date with resolution 1 day.
+ echo "$DATE_CURRENT_SHORT";
+} # Get YYYYmmdd
+timeDuration(){
+ # Desc: Output approximate time duration string before given time (default:current date)
+ # Ref/Attrib: ISO-8601:2004(E), §4.4.4.2 Representations of time intervals by duration and context information
+ # Note: "1 month" ("P1M") is assumed to be "30 days" (see ISO-8601:2004(E), §2.2.1.2)
+ # Usage: timeDuration [arg1] ([arg2])
+ # Input: arg1: seconds as base 10 integer >= 0 (ex: 3601)
+ # arg2: precision level (optional; default=2)
+ # Output: stdout: ISO-8601 duration string (ex: "P1H1S", "P2Y10M15DT10H30M20S")
+ # Example: 'timeDuration 111111 3' yields 'P1DT6H51M'
+ # Depends: date 8 (gnucoreutils)
+ local returnState fullHours fullMinutes fullSeconds;
+ ARG1="$1";
+ ARG2="$2";
+ precision=2; # set default precision
+ returnState="true"; # set default return state
+
+ # Check that between one and two arguments is supplied
+ if ! { [[ $# -ge 1 ]] && [[ $# -le 2 ]]; }; then
+ yell "ERROR:Invalid number of arguments:$# . Exiting.";
+ returnState="ERROR_INPUT"; fi
+
+ # Check that arg1 provided
+ if [[ $# -ge 1 ]]; then
+ # Check that arg1 is a positive integer
+ if [[ "$ARG1" =~ ^[[:digit:]]+$ ]]; then
+ arg1Valid="true";
+ else
+ yell "ERROR:ARG1 not a digit.";
+ returnState="ERROR_INPUT";
+ arg1Valid="false";
+ fi
+ else
+ yell "ERROR:No argument provided. Exiting.";
+ exit 1;
+ fi
+
+ # Consider whether arg2 was provided
+ if [[ $# -eq 2 ]]; then
+ # Check that the second arg is a positive integer
+ if [[ "$ARG2" =~ ^[[:digit:]]+$ ]] && [[ "ARG2" -gt 0 ]]; then
+ arg2Valid="true";
+ precision="$ARG2";
+ else
+ yell "ERROR:ARG2 not a positive integer. (is $ARG2 ). Leaving early.";
+ returnState="ERROR_INPUT";
+ arg2Valid="false";
+ fi;
+ else
+ arg2Valid="false";
+ fi;
+
+ remainder="$ARG1" ; # seconds
+ ## Calculate full years Y, update remainder
+ fullYears=$(( remainder / (365*24*60*60) ));
+ remainder=$(( remainder - (fullYears*365*24*60*60) ));
+ ## Calculate full months M, update remainder
+ fullMonths=$(( remainder / (30*24*60*60) ));
+ remainder=$(( remainder - (fullMonths*30*24*60*60) ));
+ ## Calculate full days D, update remainder
+ fullDays=$(( remainder / (24*60*60) ));
+ remainder=$(( remainder - (fullDays*24*60*60) ));
+ ## Calculate full hours H, update remainder
+ fullHours=$(( remainder / (60*60) ));
+ remainder=$(( remainder - (fullHours*60*60) ));
+ ## Calculate full minutes M, update remainder
+ fullMinutes=$(( remainder / (60) ));
+ remainder=$(( remainder - (fullMinutes*60) ));
+ ## Calculate full seconds S, update remainder
+ fullSeconds=$(( remainder / (1) ));
+ remainder=$(( remainder - (remainder*1) ));
+ ## Check which fields filled
+ if [[ $fullYears -gt 0 ]]; then hasYears="true"; else hasYears="false"; fi
+ if [[ $fullMonths -gt 0 ]]; then hasMonths="true"; else hasMonths="false"; fi
+ if [[ $fullDays -gt 0 ]]; then hasDays="true"; else hasDays="false"; fi
+ if [[ $fullHours -gt 0 ]]; then hasHours="true"; else hasHours="false"; fi
+ if [[ $fullMinutes -gt 0 ]]; then hasMinutes="true"; else hasMinutes="false"; fi
+ if [[ $fullSeconds -gt 0 ]]; then hasSeconds="true"; else hasSeconds="false"; fi
+
+ ## Determine which fields to display (see ISO-8601:2004 §4.4.3.2)
+ witherPrecision="false"
+
+ ### Years
+ if $hasYears && [[ $precision -gt 0 ]]; then
+ displayYears="true";
+ witherPrecision="true";
+ else
+ displayYears="false";
+ fi;
+ if $witherPrecision; then ((precision--)); fi;
+
+ ### Months
+ if $hasMonths && [[ $precision -gt 0 ]]; then
+ displayMonths="true";
+ witherPrecision="true";
+ else
+ displayMonths="false";
+ fi;
+ if $witherPrecision && [[ $precision -gt 0 ]]; then
+ displayMonths="true";
+ fi;
+ if $witherPrecision; then ((precision--)); fi;
+
+ ### Days
+ if $hasDays && [[ $precision -gt 0 ]]; then
+ displayDays="true";
+ witherPrecision="true";
+ else
+ displayDays="false";
+ fi;
+ if $witherPrecision && [[ $precision -gt 0 ]]; then
+ displayDays="true";
+ fi;
+ if $witherPrecision; then ((precision--)); fi;
+
+ ### Hours
+ if $hasHours && [[ $precision -gt 0 ]]; then
+ displayHours="true";
+ witherPrecision="true";
+ else
+ displayHours="false";
+ fi;
+ if $witherPrecision && [[ $precision -gt 0 ]]; then
+ displayHours="true";
+ fi;
+ if $witherPrecision; then ((precision--)); fi;
+
+ ### Minutes
+ if $hasMinutes && [[ $precision -gt 0 ]]; then
+ displayMinutes="true";
+ witherPrecision="true";
+ else
+ displayMinutes="false";
+ fi;
+ if $witherPrecision && [[ $precision -gt 0 ]]; then
+ displayMinutes="true";
+ fi;
+ if $witherPrecision; then ((precision--)); fi;
+
+ ### Seconds
+
+ if $hasSeconds && [[ $precision -gt 0 ]]; then
+ displaySeconds="true";
+ witherPrecision="true";
+ else
+ displaySeconds="false";
+ fi;
+ if $witherPrecision && [[ $precision -gt 0 ]]; then
+ displaySeconds="true";
+ fi;
+ if $witherPrecision; then ((precision--)); fi;
+
+