Calculate the duration (in seconds) of a process based on its log file entries.

runtime.sh

timestamp() {
  date -j -f "%Y-%m-%d%H:%M:%S" $* +%s
}

extract_time_field(){
  echo $* | awk '{print $1$2}' | awk -F',' '{print $1}'
}

for logfile in `ls *.log`; do
  starttime=$(extract_time_field $(cat $logfile | head -n1))
  endtime=$(extract_time_field $(cat $logfile | tail -n1))
  difference=$(expr $(timestamp $endtime) - $(timestamp $starttime))

  echo "$logfile: Duration (seconds): $difference"
done

The input log files are expected to be in the following format (only the date/time stamps are important):

2013-08-03 23:01:03,452 ... first message.
Etc.
2013-08-03 23:00:01,562 ... last message.

Put all the log files in the same directory as the script and run it.

Milliseconds are discarded.

Example output:

foo.log: Duration (seconds): 79
bar.log: Duration (seconds): 4
baz.log: Duration (seconds): 33
qux.log: Duration (seconds): 74