Regex with sed, search across multiple lines

Question

I\'d like to concatenate a few lines, perform a regex match on them and print them. I tried to do that with sed.

Namely, I used:

cat add | sed -rn \'/FIR         


        

Answer 1

sed -n '/FIRST_LINE_REGEX/,/LAST_LINE_REGEX/p' add | sed -n '/FIRST_LINE_REGEX/ b check; H; $ b check; b; :check; x; /SOME_REGEX/p'

The motivation of the second pipe part comes from here: https://stackoverflow.com/a/6287105/992834

Edit: Amended for when SOME_REGEX is in between.