After doing some scripting in a log file, I am left with some lines like this.

10:00:00 Received Message Message ID 1
10:05:00 Published Message Message ID 1
10:10:00 Received Message Message ID 2
10:15:00 Published Message Message ID 2
10:20:00 Received Message Message ID 3
10:26:00 Published Message Message ID 3
10:30:00 Received Message Message ID 4
10:37:00 Published Message Message ID 4
10:40:00 Received Message Message ID 5
10:48:00 Published Message Message ID 5


I would like to have my output like this (difference between received and published messages with message id)

Message ID 1: 5
Message ID 2: 5
Message ID 3: 6
Message ID 4: 7
Message ID 5: 8

Any simple direct shell script for this?

I suppose the time format is "hh:mm:ss" and you want the output expressed in minutes:

awk '
   {
      if (++x[$NF]>1) {
         split($1,curr_time,":");
         interval=(curr_time[1]*3600+curr_time[2]*60+curr_time[3]) - \
                  (prev_time[1]*3600+prev_time[2]*60+prev_time[3]);
         print("Message ID "$NF": "interval/60);
      } else {
         split($1,prev_time,":");
      }
   }
' input_file