Shell Programming and Scripting

linecount=$(cat -n http.log | grep ALERT | awk '{print $1}' | wc -l)
lines=$(cat -n http.log | grep ALERT | awk '{print $1}')

cat -n http.log | grep ALERT | awk '{print $1}' > lines # to record needed string numbers in file
for i in $(seq 1 $linecount); do
let line$i=$(sed -n "$i" p lines) # to define each line number as variable :D i know that`s ugly
sed -n 'line$ip;line$i+1p;line$i+2p;...' http.log  # that`s the ugliest ever, and that doesn`t work. Any suggestions?
done

#!/bin/bash
linecount=$(cat -n http.log | grep ALERT | awk '{print $1}' | wc -l)
lines=$(cat -n http.log | grep ALERT | awk '{print $1}')
cat -n http.log | grep ALERT | awk '{print $1}' > lines
#echo $lines > lines # V RYADOK, SYKA
for i in $(seq 1 $linecount); do
let line$i=$(sed -n "$i"p lines) #echo $[line$i]
sed -n "$[line$i]p;$(($[line$i]+1))p;$(($[line$i]+2))p;$(($[line$i]+3))p;$(($[line$i]+4))p" http.log | awk '{sub(/^[ \t]+/, ""); print}' >> alerts
done