Question

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 -i null myfile.txt returns

example two null,
example four null,

How can I return matched lines together with their line numbers like this:

  example two null, - Line number : 2
  example four null, - Line number : 4
  Total null count : 2

I know -c returns total matched lines, but I don’t how to format it properly to add total null count in front, and I don’t know how to add the line numbers.

What can I do?

Answer 1

-n returns line number.

-i is for ignore-case. Only to be used if case matching is not necessary

$ grep -in null myfile.txt

2:example two null,
4:example four null,

Combine with awk to print out the line number after the match:

$ grep -in null myfile.txt | awk -F: '{print $2" - Line number : "$1}'

example two null, - Line number : 2
example four null, - Line number : 4

Use command substitution to print out the total null count:

$ echo "Total null count :" $(grep -ic null myfile.txt)

Total null count : 2