Вложите предыдущую версию объекта, в спящем режиме Envers

Я использую timeout для тайм-аута tail и использую некоторый файл сохранения для сохранения позиции строки, которую мы проанализировали:

# statefile where we save the number of parsed already lines
statefile=/tmp/statefile.txt

# initialize count variable - to zero, or from statefile
if [ -e "$statefile" ]; then
    count=$(<"$statefile")
else
    count=0
fi

# we timeout for 1 seconds outputting the lines
# the better timeout would be like 10 seconds for big file
# the `tail` command needs to jump `$count` lines inside the input file
timeout 1 tail -n +$count input_log_file |
# tee is used to pass the input to the updating part
tee >(
     # read number of parsed lines with `wc -l`
     # increment the count of parsed lines and save to statefile
     echo $(( count + $(wc -l) )) >"$statefile"
) |
# grep for the searched string
grep --line-buffered string_to_search |
# do the action if string_to_search is found
do_some_action_example_send_mail