+ # 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;
+
+
+
+ ## Determine whether or not the "T" separator is needed to separate date and time elements
+ if ( $displayHours || $displayMinutes || $displaySeconds); then
+ displayDateTime="true"; else displayDateTime="false"; fi
+
+ ## Construct duration output string
+ OUTPUT="P"
+ if $displayYears; then
+ OUTPUT=$OUTPUT$fullYears"Y"; fi
+ if $displayMonths; then
+ OUTPUT=$OUTPUT$fullMonths"M"; fi
+ if $displayDays; then
+ OUTPUT=$OUTPUT$fullDays"D"; fi
+ if $displayDateTime; then
+ OUTPUT=$OUTPUT"T"; fi
+ if $displayHours; then
+ OUTPUT=$OUTPUT$fullHours"H"; fi
+ if $displayMinutes; then
+ OUTPUT=$OUTPUT$fullMinutes"M"; fi
+ if $displaySeconds; then
+ OUTPUT=$OUTPUT$fullSeconds"S"; fi