Shell Programming and Scripting

Hello everyone, I'me new to shell scripting and have been trying to create a custom script to do the following steps -

1. search for the word servicedown within all log files in a specific directory
2. After finding the keyword servicedown, grab latest timestamp from that log
3. Set variable with results from #2
4. loop previous log files and grab the timestamp from the last line from next newest log in that directory.
5. Set a variable with the results from #4
5. Calculate difference between the 2 timestamps in minutes.

Here is what I have so far, and it's very incomplete. I've been trying to piece this script together as best as I can and could really use any help I can get.

Code:

#!/sw/bin/bash


LogFile="abc.server-ny-abc01.200908270000+0000.log"

LogFile2="$(ls -lt /abc01/ihost/log/abc*log|/sw/bin/grep -v abc.log|/sw/bin/grep -A 1 $LogFile| /sw/bin/tail -n 1| /sw/bin/sed -n "s/.*\(abc\..*\)/\1/p")"

/sw/bin/tail -n 1 /abc01/imail/log/$LogFile2 | /sw/bin/awk '{print "Crash Start",substr($0,1, 13)}'
/sw/bin/grep -i "servicedown" /abc01/ihostlog/abc.log | /sw/bin/awk '{print "Crash End",substr($0,1, 13)}'

exit 0

Here is the current format of the logfiles being generated.-
abc.server-ny-abc01.200908270000+0000.log

Please make it emphatically clear where to find "timestamp", stating the units, layout and precision of "timestamp".
I may be being thick, but I can't see any code to save the timestamp of the "servicedown" event or to save the timestamp of the logfile prior to the event.

It might help to see a directory listing of the three directories mentioned in the script:
/abc01/ihost/log/
/abc01/imail/log/
/abc01/ihostlog/
Or you could view this request as a hint about a possible problem .... ?