I\'m using grep to match string in a file. Here is an example file:
example one,
example two null,
example three,
example four null,
grep
grep
find the lines and output the line numbers, but does not let you "program" other things. If you want to include arbitrary text and do other "programming", you can use awk,
$ awk '/null/{c++;print $0," - Line number: "NR}END{print "Total null count: "c}' file
example two null, - Line number: 2
example four null, - Line number: 4
Total null count: 2
Or only using the shell(bash/ksh)
c=0
while read -r line
do
case "$line" in
*null* ) (
((c++))
echo "$line - Line number $c"
;;
esac
done < "file"
echo "total count: $c"