convert a DURATION HH:MM:SS to seconds in bash

          var reptms = /^PT(?:(\d+)H)?(?:(\d+)M)?(?:(\d+)S)?$/;
          var hours = 0, minutes = 0, seconds = 0, totalseconds;

          if (reptms.test(input)) {
            var matches = reptms.exec(input);
            if (matches[1]) hours = Number(matches[1]);
            if (matches[2]) minutes = Number(matches[2]);
            if (matches[3]) seconds = Number(matches[3]);
            totalseconds = hours * 3600  + minutes * 60 + seconds;
          }

concat(floor($NUMSEC div 86400),' Days ',floor($NUMSEC div 3600) mod 24,' Hours ',
  floor($NUMSEC div 60) mod 60,' Minutes ',$NUMSEC mod 60,' Seconds'

v1 <- strptime(durations, format='%H:%M:%S')
v1$hour * 3600 + v1$min * 60 + v1$sec
#[1] 3661

c(unlist(unclass(v1)[c("hour", "min", "sec")]) %*% c(3600, 60, 1))

select datediff(second, 0, cast('00:' + right('0' + duration, 5) as time))

select cast(left(duration, charindex(':', t) - 1) as int)*60 + cast(right(duration, 2) as int)

System.out.println(duration.getSeconds()%60);

System.out.println(duration.getSeconds() - duration.toMinutes()*60);

System.out.println(duration.toSecondsPart());