for+if+var

grep -n  ^_id mongo.txt  | awk -F: '{print $1}' > num.txt
table_count=`cat -n tables.txt  | awk '{print $1}' | tail -n 1`
target_row_count=`wc -l num.txt | awk '{print $1}'`
for ((i=1; i<=$target_row_count; i++));
do
	for ((j=1; j<=$table_count; j++));
	do 
		row=`sed -n ''"$i"'p' num.txt`
		row=`expr $row + $i - 1`
		table=`sed -n ''"$j"'p' tables.txt`
		if [ $i == $j ]
		then
			sed -i ''"$row"'i'"$table"'' pinsurvey-mongo.txt
		fi
	done
done