Grep command that matches lines with EXACTLY 2 '*'

Question

I need help figuring out a command that will search a file and display lines that include exactly 2 *.

• Valid matches examples: **, *red*, manche*ste*r
• Invalid matches examples: *, ***, mache*s*te*r

What I have so far is:

grep ‘\*.*\*’ filename.txt

But this displays lines that have at least two * but not exactly two. And I can't see to find a way to do that.

Answer 1

You may use

grep '^[^*]*\*[^*]*\*[^*]*$' filename.txt

The regex matches a string that contains exactly two asterisks with any other chars before, after and in-between them.

Pattern details

• ^ - start of string
• [^*]* - 0+ chars other than *
• \* - a *
• [^*]*\*[^*]* - 0+ chars other than *, a * and again 0+ chars other than *
• $ - end of string.