Lines per second in a log file

tail -F some.log | perl -ne 'print time(), "\n";' | uniq -c

2
By: grana
2013-05-11 04:51:22

7 Alternatives + Submit Alt

  • Displays the realtime line output rate of a logfile. -l tels pv to count lines -i to refresh every 10 seconds -l option is not in old versions of pv. If the remote system has an old pv version: ssh tail -f /var/log/apache2/access.log | pv -l -i10 -r >/dev/null


    10
    tail -f access.log | pv -l -i10 -r >/dev/null
    dooblem · 2010-04-29 21:02:01 0
  • The cut should match the relevant timestamp part of the logfile, the uniq will count the number of occurrences during this time interval. Show Sample Output


    5
    grep <something> logfile | cut -c2-18 | uniq -c
    buzzy · 2010-04-29 11:26:09 0
  • Using tail to follow and standard perl to count and print the lps when lines are written to the logfile.


    5
    tail -f /var/log/logfile|perl -e 'while (<>) {$l++;if (time > $e) {$e=time;print "$l\n";$l=0}}'
    madsen · 2011-06-21 10:28:26 3
  • Another way of counting the line output of tail over 10s not requiring pv. Cut to have the average per second rate : tail -n0 -f access.log>/tmp/tmp.log & sleep 10; kill $! ; wc -l /tmp/tmp.log | cut -c-2 You can also enclose it in a loop and send stderr to /dev/null : while true; do tail -n0 -f access.log>/tmp/tmp.log & sleep 2; kill $! ; wc -l /tmp/tmp.log | cut -c-2; done 2>/dev/null


    1
    tail -n0 -f access.log>/tmp/tmp.log & sleep 10; kill $! ; wc -l /tmp/tmp.log
    dooblem · 2010-04-29 21:23:46 0
  • This is similar to standard `pv`, but it retains the rate history instead of only showing the current rate. This is useful for spotting changes. To do this, -f is used to force pv to output, and stderr is redirected to stdout so that `tr` can swap the carriage returns for new lines. (doesn't work correctly is in zsh for some reason. Tail's output isn't redirected to /dev/null like it is in bash. anyone know why? ???????) Show Sample Output


    1
    tail -f access.log | pv -l -i10 -r -f 2>&1 >/dev/null | tr /\\r \ \\n
    varenc · 2020-04-19 02:07:40 24

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