tail and grep a file, send mail when each line occurs

tail-grep-mail.sh

#!/bin/sh

sj=$1
to=$2
in=$3
on=$4

echo "sj=$sj"
echo "to=$to"
echo "in=$in"
echo "on=$on"

tail -fn 0 $in |
  grep --line-buffered $on |
    while read line
      do
        echo "$(date +%Y/%m/%d-%T%Z%z) - $line"
        echo "$line" | mail -s $sj $to
      done