Note: You may find adding edate and etime commands to your ~/.bashrc (or equivalent) useful:

function edate {
  local unixsec=$(date +%s)
  local unixday=$((unixsec/86400.0))
  printf "%.5f\n" $unixday
}

function etime {
 local unixday=$(edate)
 local daytime=${unixday##*.}
 echo ${daytime:0:1}:${daytime:1:2}:${daytime:3:5}
}

Command usage looks like so:

$ edate
18988.06455

$ etime
0:64:55

.