watch a log with tail -f and a fifo to run command when a grep match is made

fifo_logwatch.sh

#!/bin/bash
#fifo_logwatch.sh -jrelo
if [ $# -lt 1 ];
  then
  printf "Usage: $0 <logfile>\n" $#
  exit 0
fi

trap ctrl_c INT
fifo=/tmp/fifolog.$$
mkfifo "${fifo}" || exit 1
logfile=$1

function ctrl_c() {
  echo "ctrl^c caught. exiting..."
  rm "${fifo}"
  exit 130;
}

while sleep 1
do
  tail -fn0 ${logfile} >${fifo} &
  tailpid=$!
  grep -m 1 "Too many open files" "${fifo}"
  if [[ $? -eq 0 ]]; then 
    ulimit -n;sysctl fs.file-nr ; sysctl fs.file-max ; lsof -n|awk '{print $1}'|sort|uniq -c|sort -n 
  fi
done
#kill "${tailpid}" #uncomment if you want it to die after first match
rm "${fifo}"