CODEWITHSUNDEEP
bashshellloops
Jobine23
Jobine23

Reputation: 130

Get old value from a loop

I want to to check every 3 second if the difference of the numbers is higher than 1000. How can I get the old value, for example: 16598, every time?

while true; do 
    testbro=$(wc -l < /home/web/log/access.log)
    echo $testbro
    sleep 3 
done

It outputs as wanted:

16414
16471
16533
16598
16666

Upvotes: 1

Views: 51

Answers (1)

codeforester
codeforester

Reputation: 42999

If your intention is to detect when your file grows >= 1000 lines in a 3 second period, you could do this:

#!/bin/bash

last_size=$(wc -l < /home/web/log/access.log)
while true; do
  sleep 3
  curr_size=$(wc -l < /home/web/log/access.log)
  if ((curr_size - last_size >= 1000)); then
    echo "$curr_size"
  fi
  last_size=$curr_size
done

Upvotes: 2

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