#!/bin/bash
LOG_FILE=/var/log/sample.log
ERROR_FILE=errors_$(date +%d-%m-%y).log
TO_EMAIL_ADDRESS=ops@example.com
FROM_EMAIL_ADDRESS=from@example.com
LIMIT_SIZE=10240
ERROR_FILE_SIZE=du $ERROR_FILE

function get_errors {

grep ERROR $LOG_FILE |while read line
do
  echo $line >> $ERROR_FILE
done

}

function send_mail {

}

function send_error_mail {

}

get_errors

if [[ $ERROR_FILE_SIZE -lt $LIMIT_SIZE ]]
  then send_mail
else
  send_error_mail
fi