Write export files with timestamp

I called export at three different times and noticed that the files I got were labeled as the following:

dgraph.r60003.u0214.2201
dgraph.r70002.u0217.1905
dgraph.r70002.u0217.1906

Is there a particular format that the timestamp used here follows? Can it be replaced with, for example, a Unix timestamp?

You can choose the prefix where export directories are created, you cannot control the names of the new directories and the files. The format of the timestamp is as follows:

u<month 2 letter><date 2 letter>.<hour 2 letter, 24 hour format><minute 2 letter>

This is workable, thanks.