Convert durations to canonical format.
Optionally:
- truncate the output to give duration amount
- divide each value by given integer
$ durcan -truncate-to 5s 3600s 6s 1s
3600s = 1h0m0s
6s = 5s
1s = 0s
$ durcan -truncate-to 5s -div-by 2 3600s 6s 1s
3600s = 1h0m0s
div-by 2 = 30m0s
6s = 5s
div-by 2 = 0s
1s = 0s
div-by 2 = 0s