How to insert text in last convergence in bash?

Question

bash

Good day! Can you please tell me how to insert a line in the last convergence using bash? For example, you have a file that contains the following text:
one
two
three
two You
want to insert some text at the last occurrence of two in the entire file.

Answer 1

echo -e "one\ntwo\nthree\ntwo\nfour\ntwo\nfive" | tac | sed '/^two$/ { x; /./! { g; s/.*/xxx\n&/; }; }' | tac

Conclusion

one
two
three
two
four
two
xxx
five