Watch log dir for new file, automatically tail to slack We have a process that outputs to log files in the format /var/log/xxx/YYYY_MM_DD.log - the file name is chosen programmatically and is not rotated using logrotate or anything like that. We want to automatically tail the latest file and pipe that to slackcat so that we can see the logs in a certain slack channel.

I came up with the following solution that works great, but I'm no bash expert so I am wondering if this could be simplified? The hardest part was avoiding zombie processes when something dies or gets killed, but I'd love to do this with one file instead of 2 also:

watchlogdir.sh

#!/bin/sh
trap "pkill -TERM -g $$; exit" INT TERM EXIT
    while true; do
      /root/tailtoslack.sh &amp;
      PID=$!
      echo $PID
      echo $$
  inotifywait -e create /var/log/xxx/
  pkill -TERM -P $PID
  kill $PID
done


tailtoslack.sh

while true; do
    FILETOWATCH=`ls -t /var/log/xxx/*.log | head -1`
    tail $FILETOWATCH -f -n1 | grep -v "DEBUG:\|^$" --color=never --line-buffered | /root/slackcat &amp;&gt; /tmp/slackcat
    sleep 31
done


The core of watchlogdir.sh, besides the interruption handling stuff, is using inotifywait to watch for a new file created in the log directory, and when that happens, killing tailtoslack.sh and respawning it so it can find the new file

tailtoslack.sh just looks for the latest file, and pipes that to slackcat after filtering out DEBUG lines and empty lines. the while loop here is because some lines in the error logs cause slackcat to crash, so this way if that happens it'll sleep for a little while and retry.

Without changing the requirements of how the log files are written, can any of this be done better?
This seems quite fine. Given your circumstances, I don't see how this can be done simpler.

The script could use a bit of tidying up though. The indentation of watchlogdir.sh is haphazard, it would be more readable to make it consistent. Oh I see now. It's the $$ that messes things up, your formatting is fine.

In the other script, this line could be written better:


FILETOWATCH=`ls -t /var/log/xxx/*.log | head -1`



By using $(...) instead of `...` for command substitution, and using the canonical option -n1 instead of -1 with head:

FILETOWATCH=$(ls -t /var/log/xxx/*.log | head -n1)