Notepad ++ Find String and place symbol at beginning of line

I have 5000 lines. I need to find if a line contains a certain word phrase such as "package" and put a "1%" at the beginning of it. How would I do this with replace in notepad++?

An example being:

DOGS AND CATS

if the line contains the word "DOGS" anywhere in the string make the new line:

1% DOGS AND CATS

Solution 1:

• Ctrl+H
• Find what: ^(?=.*DOGS)
• Replace with: %1
• CHECK Match case
• CHECK Wrap around
• CHECK Regular expression
• UNCHECK . matches newline
• Replace all

Explanation:

^               # beginning of line
(?=.*DOGS)      # positive lookahead, make sure we have DOGS somewhere in the line

Screenshot (before):

Screenshot (after):