Shell Programming and Scripting

# # first time in start at top of file
typeset -i prev_lines=0
typeset -i loop_cnt=0

# # until script is killed do work
while true; do
  typeset -i cur_lines=$(wc -l /var/adm/messages | awk '{print $1}')
  if (( $cur_lines > $prev_lines )); then
    typeset -i error_cnt=$(tail +${prev_lines} /var/adm/messages | grep -c "error 102")
    let prev_lines=$cur_lines
    # # if this is not the first look at the log, then alert, else increment counter and wait 15 minutes
    if (( $loop_cnt > 0 )) && (( $error_cnt > 0 )); then
      # # send alert
      echo "alert $error_cnt number of errors found"
    else
      # # increment loop_cnt
      typeset -i loop_cnt=1
    fi
  else
    # # reset counters because log file rotated
    typeset -i prev_lines=0
    typeset -i loop_cnt=0
  fi
  # # sleep 15 minutes
  sleep 900
done