Difference in date time

Question

I have 2 variables.

GMDCOMTM which stores the date time Tue Oct  1 13:32:40 2013
GMDRRSTM which stores the date time Tue Oct  2 23:35:33 2013

H

Answer 1

C=$(date -d "Tue Oct  1 13:32:40 2013" +%s)
R=$(date -d "Tue Oct  2 23:35:33 2013" +%s)
T=$(date --date=@$((R-C))  +%H:%M:%S)