Count The Number Of Matches In A Grep

My go to way of counting the number of matches in a grep of a file is to pipe it to another command — wc.

Here is what that looks like with the README for this repo. This counts the number of lines that start with ###.

$ grep '^###' README.md | wc -l
      48

When wc is used with the -l flag, it gives a count of the number of lines. In this case the number of grep matches that get piped to it.

There is another way to do this solely with the grep command — using the -c flag.

$ grep -c '^###' README.md
48

When you include the -c (or --count) flag with grep, instead of the matches being output, the count of the matches is output.

See man grep for more details.